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  • 1. Björ, Bodil
    et al.
    Burström, Lage
    Liljelind, Ingrid
    Lundström, Ronnie
    Nilsson, Tohr
    Wahlström, Jens
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Cold health impacts in northern Sweden2016In: International Journal of Circumpolar Health, ISSN 1239-9736, E-ISSN 2242-3982, Vol. 75, no 33200Article in journal (Refereed)
  • 2. Boschman, J S
    et al.
    Noor, A
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Sluiter, J K
    Hagberg, M
    Relationships between work-related factors and musculoskeletal health with current and future work ability among male workers2017In: International Archives of Occupational and Environmental Health, ISSN 0340-0131, E-ISSN 1432-1246, Vol. 90, no 6, p. 517-526Article in journal (Refereed)
    Abstract [en]

    PURPOSE: The purpose was to increase job-specific knowledge about individual and work-related factors and their relationship with current and future work ability (WA). We studied cross-sectional relationships between mental demands, physical exertion during work, grip strength, musculoskeletal pain in the upper extremities and WA and the relationships between these variables and WA 11 years later.

    METHODS: We used a dataset of a prospective cohort study (1997-2008) among employees of an engineering plant (n = 157). The cohort was surveyed by means of tests and written questions on work demands, musculoskeletal health, WA score (WAS; 0-10), and mental and physical WA. Spearman correlation coefficients and logistic regression analysis were used.

    RESULTS: Among manual workers, we found weak correlations between grip strength and current and future physical WA. We did not find predictors for future poor WA among the manual workers. Among the office workers, we found that musculoskeletal pain was moderately and negatively related to current WAS and physical WA. More handgrip strength related to better future WAS and physical WA. Musculoskeletal pain (OR 1.67 p < 0.01) and lower handgrip strength (OR 0.91 p < 0.05) predicted future poor WA among office workers.

    CONCLUSIONS: Our results showed cross-sectional and longitudinal relationships between musculoskeletal health and work ability depending on occupation. However, the present implies that predicting work ability in the far future based on health surveillance data is rather difficult. Testing the musculoskeletal system (grip strength) and asking workers' about their musculoskeletal health seems relevant when monitoring work ability.

  • 3.
    Burström, Lage
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, Box 414, SE-405 30 Gothenburg, Sweden.
    Liljelind, Ingrid
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundström, Ronnie
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Nilsson, Tohr
    Department of Occupational and Environmental Medicine, Sundsvall Hospital, Sundsvall, SE-851 86 Sweden.
    Pettersson, Hans
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Wahlström, Jens
    Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, Box 414, SE-405 30 Gothenburg, Sweden.
    A follow-up study of welders’ exposure to vibration in a heavy engineering production workshop2010In: Journal of Low Frequency Noise Vibration and Active Control, ISSN 0263-0923, Vol. 29, no 1, p. 33-39Article in journal (Refereed)
    Abstract [en]

    Manual work involving vibrating power tools is associated with symptoms that include vascular, neurological and musculoskeletal disorders. This study examines the vibration exposure of welders to determine the change between 1987 and 2008. Vibration measurements on handheld tools were used to evaluate the acceleration and the daily exposure time was determined by subjective rating. From these data, the 8-hour equivalent vibration exposure A(8), has been calculated. During the period, the A(8) decreased from 3.9 m/s2 to 1.9 m/s2. It was concluded that this decrease is the result of fewer vibrating tools and a decrease in daily exposure time. Although the daily vibration exposure has decreased over the study time, for some welders the daily vibration exposure A(8) is still above the action value set by the EU directive on vibration. This means more effort should be spent to decrease vibration exposure.

  • 4.
    Burström, Lage
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Influence of vibration exposure on tactile and thermal perception thresholds2009In: Occupational Medicine, ISSN 0962-7480, E-ISSN 1471-8405, Vol. 59, no 3, p. 174-9Article in journal (Refereed)
    Abstract [en]

    AIMS: To establish if intermittent exposure to hand-transmitted vibration had the same effect as continuous exposure on the temporary response of finger tactile and thermal perception thresholds. METHODS: Two laboratory experiments were conducted. In each, 10 healthy subjects, five males and five females, participated. The subjects' fingers were exposed to vibration under four conditions with a combination of different periods of exposure and rest periods. The vibration frequency was 125 Hz and the frequency-weighted acceleration was 5 m/s(2). A measure of the tactile or thermal perception was conducted before the different exposures to vibration. Immediately after the vibration exposure, the acute effect was measured continuously for the first 75 s. This was followed by regular measures for a maximum of 30 min. RESULTS: The results showed that combinations of vibration with different periods of exposure and rest periods significantly influenced vibrotactile perception, but not thermal perception. CONCLUSIONS: These findings suggest that intermittent exposure to hand-transmitted vibration might be more beneficial for the response of the finger vibrotactile sensation than continuous exposure. This finding is inconsistent with the evaluation methods in ISO 5349-1 for vibrotactile sensation, but accurate for thermal perception.

  • 5.
    Burström, Lage
    et al.
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Hagberg, Mats
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine. Umeå University, Faculty of Medicine, Radiation Sciences.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Relationship between hand-arm vibration exposure and onset time for symptoms in a heavy engineering production workshop.2006In: Scandinavian journal of work, environment & health, ISSN 0355-3140, Vol. 32, no 3, p. 198-203Article in journal (Refereed)
  • 6.
    Burström, Lage
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Vibrotactile perception and effects of short-term exposure to hand-arm vibration2009In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 53, no 5, p. 539-547Article in journal (Refereed)
    Abstract [en]

    This study clarifies whether the established frequency weighting procedure for evaluating exposure to hand-transmitted vibration can effectively evaluate the temporary changes in vibrotactile perception thresholds due to pre-exposure to vibration. In addition, this study investigates the relationship between changes of the vibrotactile perception thresholds and the normalized energy-equivalent frequency-weighted acceleration. The fingers of 10 healthy subjects, five male and five female, were exposed to vibration under 16 conditions with a combination of different frequencies, intensities, and exposure times. The vibration frequencies were 31.5 and 125 Hz and exposure lasted between 2 and 16 min. According to International Organization for Standardization (ISO) 5349-1, the energy-equivalent frequency-weighted acceleration for the experimental time of 16 min is 2.5 or 5.0 m s(-2) root-mean-square, corresponding to a 8-h equivalent acceleration, A(8), of approximately 0.5 and 0.9 m s(-2), respectively. A measure of the vibrotactile perception thresholds was conducted before the different exposures to vibration. Immediately after the vibration exposure, the acute effect was measured continuously on the exposed index finger for the first 75 s, followed by 30 s of measures every minute for a maximum of 10 min. If the subject's thresholds had not recovered, the measures continued for a maximum of 30 min with measurements taken every 5 min. Pre-exposure to vibration significantly influenced vibrotactile thresholds. This study concludes that the influence on the thresholds depends on the frequency of the vibration stimuli. Increased equivalent frequency-weighted acceleration resulted in a significant change in threshold, but the thresholds were unaffected when changes in the vibration magnitude were expressed as the frequency-weighted acceleration or the unweighted acceleration. Moreover, the frequency of the pre-vibration exposure significantly influenced (up to 25 min after exposure) recovery time of the vibrotactile thresholds. This study shows that the frequency weighting procedure in ISO 5349-1 is unable to predict the produced acute changes in the vibrotactile perception. Moreover, the results imply that the calculation of the 'energy-equivalent' frequency-weighted acceleration does not reflect the acute changes of the vibration perception thresholds due to pre-exposure to vibration. Furthermore, when testing for the vibrotactile thresholds, exposure to vibration on the day of a test might influence the results. Until further knowledge is obtained, the previous practice of 3 h avoidance of vibration exposure before assessment is recommended.

  • 7.
    Burström, Lage
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Sjödin, Fredrik
    National Institute for Working Life Department of Work and the Physical Environment Umeå Sweden.
    Lindmark, Asta
    National Institute for Working Life Department of Work and the Physical Environment Umeå Sweden.
    Lindkvist, Markus
    University Hospital of Northern Sweden Department of Biomedical Engineering and Informatics Umeå Sweden.
    Hagberg, Mats
    Sahlgrenska University Hospital Department of Occupational and Environmental Medicine Gothenburg Sweden.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Acute effects of vibration on thermal perception thresholds2008In: International Archives of Occupational and Environmental Health, ISSN 0340-0131, E-ISSN 1432-1246, Vol. 81, no 5, p. 603-611Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: This study focuses on the acute effects of vibration and how vibrations influence the measures of the thermal perception thresholds during different vibration magnitudes, frequencies, and durations. METHODS: The fingers of ten healthy subjects, five males and five females, were exposed to vibration under 16 conditions with a combination of different frequency, intensity and exposure time. The vibration frequency was 31.5 and 125 Hz and exposure lasted between 2 and 16 min. The energy-equivalent frequency weighted acceleration, according to ISO 5349-1, for the experimental time of 16 min was 2.5 or 5.0 m/s(2) (r.m.s.), corresponding to a 8-h equivalent acceleration, A(8) of 0.46 and 0.92 m/s(2), respectively. A measure of the thermal perception of cold and warmth was conducted before the different exposures to vibration. Immediately after the vibration exposure the acute effect was measured continuously on the exposed index finger for the first 75 s, followed by 30 s of measures at every minute for a maximum of 10 min. If the subject's thermal thresholds had not recovered, the measures continued for a maximum of 30 min with measurements taken every 5 min. RESULTS: For all experimental conditions and 30 s after exposure, the mean changes of the thresholds compared with the pre-test were found to be 0.05 and -0.67 degrees C for the warmth and cold thresholds, respectively. The effect of the vibration exposure was only significant on the cold threshold and only for the first minute after exposure when the threshold was decreased. The warmth threshold was not significantly affected at all. The frequency and the exposure time of the vibration stimuli had no significant influence on the perception thresholds for the sensation of cold or warmth. Increased equivalent frequency weighted acceleration resulted in a significant decrease of the subjects' cold threshold, not the warmth. The thresholds were unaffected when changes in the vibration magnitude were expressed as the frequency weighted acceleration or the unweighted acceleration. CONCLUSION: When testing for the thermotactile thresholds, exposure to vibration on the day of a test might influence the results. Until further knowledge is obtained the previous praxis of 2 h avoidance of vibration exposure before assessment is recommended.

  • 8.
    Burström, Lage
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Neely, Gregory
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Occupational exposure to vibration from hand-held tools: A teaching guide on health effects, risk assessment and prevention2009Book (Other academic)
  • 9.
    Carlsson, Daniel
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Wahlström, Jens
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Avd för samhällsmedicin och folkhälsa vid Institutionen för medicin, Göteborgs universitet.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Pettersson, Hans
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Can sensation of cold hands predict Raynaud’s phenomenon or paresthesia?2018In: Occupational Medicine, ISSN 0962-7480, E-ISSN 1471-8405, Vol. 68, no 5, p. 314-319Article in journal (Refereed)
    Abstract [en]

    Background: Raynaud's phenomenon and neurosensory symptoms are common after hand-arm vibration exposure. Knowledge of early signs of vibration injuries is needed. Aims: To investigate the risk of developing Raynaud's phenomenon and paraesthesia in relation to sensation of cold hands in a cohort of male employees at an engineering plant. Methods: We followed a cohort of male manual and office workers at an engineering plant in Sweden for 21 years. At baseline (1987 and 1992) and each follow-up (1992, 1997, 2002, 2008), we assessed sensation of cold, Raynaud's phenomenon and paraesthesia in the hands using questionnaires and measured vibration exposure. We calculated risk estimates with univariate and multiple logistic regression analyses and adjusted for vibration exposure and tobacco usage. Results: There were 241 study participants. During the study period, 21 individuals developed Raynaud's phenomenon and 43 developed paraesthesia. When adjusting the risk of developing Raynaud's phenomenon for vibration exposure and tobacco use, the odds ratios were between 6.0 and 6.3 (95% CI 2.2-17.0). We observed no increased risk for paraesthesia in relation to a sensation of cold hands. Conclusions: A sensation of cold hands was a risk factor for Raynaud's phenomenon. At the individual level, reporting a sensation of cold hands did not appear to be useful information to predict future development of Raynaud's phenomenon given a weak to moderate predictive value. For paraesthesia, the sensation of cold was not a risk factor and there was no predictive value at the individual level.

  • 10. Cherniack, M
    et al.
    Brammer, A J
    Nilsson, T
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundstrom, R
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Meyer, J D
    Morse, T
    Neely, Gregory
    Peterson, D
    Toppila, E
    Warren, N
    Atwood-Sanders, M
    Michalak-Turcotte, C
    Abbas, U
    Bruneau, H
    Croteau, M
    Fu, R W
    Nerve conduction and sensorineural function in dental hygienists using high frequency ultrasound handpieces.2006In: Am J Ind Med, ISSN 0271-3586, Vol. 49, no 5, p. 313-26Article in journal (Refereed)
  • 11. Cherniack, Martin
    et al.
    Brammer, Anthony J
    Lundstrom, Ronnie
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Meyer, John D
    Morse, Tim F
    Neely, Greg
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Peterson, Donald
    Toppila, Esko
    Warren, Nicholas
    The Hand-Arm Vibration International Consortium (HAVIC): prospective studies on the relationship between power tool exposure and health effects.2007In: Journal of Occupational and Environmental Medicine, ISSN 1076-2752, E-ISSN 1536-5948, Vol. 49, no 3, p. 289-301Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The Hand-Arm Vibration International Consortium (HAVIC) is a collaboration of investigators from Europe and North America studying health effects from hand-arm vibration (HAV). Features include prospective design, cross-cohort exposure, and health assessment methods. METHODS: Two new cohorts (dental hygienists and dental hygiene students), two existing cohorts (Finnish forest workers, and Swedish truck cab assemblers), and a previous population (US shipyard workers) are included. Instruments include surveys, quantitative medical tests, physical examination, and work simulation and data logging to assess exposure. New methods were developed for nerve conduction and data logging. RESULTS: Findings on the relationship between nerve conduction and skin temperature in HAV-exposed subjects resulted in a new approach to subject warming. CONCLUSIONS: Integrating established cohorts has advantages over de novo cohort construction. Complex laboratory tests can be successfully adapted for field use.

  • 12. Cherniack, Martin
    et al.
    Brammer, Anthony J
    Lundstrom, Ronnie
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Morse, Tim F
    Neely, Greg
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Peterson, Donald
    Toppila, Esko
    Warren, Nicholas
    Diva, Ulysses
    Croteau, Marc
    Dussetschleger, Jeffrey
    The effect of different warming methods on sensory nerve conduction velocity in shipyard workers occupationally exposed to hand-arm vibration.2008In: International archives of occupational and environmental health, ISSN 1432-1246, Vol. 81, no 8, p. 1045-58Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: Segmental sensory nerve conduction velocity (SNCV) was measured from the wrists to the hands and digits in a population of 134 (126 men and 8 women) vibration-exposed shipyard workers following systemic warming using a bicycle ergometer. Results were compared to earlier nerve conduction tests, identical in execution, except that the warming process was segmental and cutaneous. The study was designed to investigate whether SNCVs, which were selectively slow in the fingers after segmental cutaneous (skin surface) warming, would be affected differently by systemic warming. METHODS: Wrist-palm, palm-proximal digit, and digital sensory nerve segments were assessed antidromically by stimulating at the wrist with recording electrodes placed distally. The same subjects were cutaneously warmed in 2001 to >or=31 degrees C and were systemically warmed 28 months later in 2004 by ramped sustained exercise to 100 W for 12 min. Skin temperatures were measured by traditional thermistry and by infrared thermal images taken over the hand and wrist surfaces. RESULTS: When systemic warming was compared to segmental cutaneous warming, SNCVs were increased by 15.1% in the third digit and 20.4% in the fifth digit of the dominant hand. Respective increases in the non-dominant hand were 11.0% and 19.4%. A strong association between increased surface skin temperature and faster SNCV, which had been observed after segmental cutaneous warming, was largely eliminated for both digit and palmar anatomic segments after systemic warming. Significant differences in SNCV between vibration-exposed and non-exposed workers, which had been observed after segmental cutaneous warming, were eliminated after systemic warming. Systemic warming had only a small effect on the wrist-palm (transcarpal) segmental SNCVs. CONCLUSIONS: Reduced SNCV in the digits was observed in vibration-exposed and non-exposed workers. Substituting exercise-induced systemic warming for segmental cutaneous warming significantly increased SNCV in the digits and appeared to reduce differences in SNCV between vibration-exposed and non-exposed workers. These findings persisted despite a substantial time interval between tests, during which the subjects continued to work. There may be more general implications for diagnosing clinical conditions in industrial workers, such as the carpal tunnel syndrome and the hand-arm vibration syndrome.

  • 13. Edlund, Maria
    et al.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Gerhardsson, Lars
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Sandén, Helena
    Hagberg, Mats
    A prospective cohort study investigating an exposure-response relationship among vibration-exposed male workers with numbness of the hands2014In: Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140, E-ISSN 1795-990X, Vol. 40, no 2, p. 203-209Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The aim of this study was to investigate the exposure-response relationship of hand-arm vibration exposure to neurological symptoms (numbness) of the hand in a cohort of vibration-exposed workers.

    METHODS: The baseline cohort comprised 241 office and manual workers with or without exposure to hand-arm vibration. Numbness (the symptom or event) in the hand was assessed for all subjects at baseline and follow-ups after 5, 10, and 16 years. The workers were stratified into quartiles with no exposure in the first quartile and increasing intensity of exposure in quartiles 2-4 (groups 1-3). Data analysis was performed using survival analysis (time to event). Information on cumulative exposure and years of exposure to event was collected via questionnaires. Measurements were performed in accordance with the International Organization for Standardization (ISO) 5349-1.

    RESULTS: The hazard ratio (HR) of risk of event (numbness) differed statistically significantly between the non-exposed group (group 0) and the two higher exposure groups (groups 2 and 3). There was also a significant ratio difference between the lowest exposure group (group 1) and the two higher groups. The ratio for group 1 was 1.77 [95% confidence interval (95% CI) 0.96-3.26] compared with 3.78 (95% CI 2.15-6.62) and 5.31 (95% CI 3.06-9.20) for groups 2 and 3, respectively.

    CONCLUSION: The results suggest a dose-response relationship between vibration exposure and numbness of the hands. This underlines the importance of keeping vibration levels low to prevent neurological injury to the hands.

  • 14. Edlund, Maria
    et al.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Sanden, Helena
    Wastensson, Gunilla
    Quantitatively measured tremor in hand-arm vibration-exposed workers2015In: International Archives of Occupational and Environmental Health, ISSN 0340-0131, E-ISSN 1432-1246, Vol. 88, no 3, p. 305-310Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to investigate the possible increase in hand tremor in relation to hand-arm vibration (HAV) exposure in a cohort of exposed and unexposed workers. Participants were 178 male workers with or without exposure to HAV. The study is cross-sectional regarding the outcome of tremor and has a longitudinal design with respect to exposure. The dose of HAV exposure was collected via questionnaires and measurements at several follow-ups. The CATSYS Tremor Pen(A (R)) was used for measuring postural tremor. Multiple linear regression methods were used to analyze associations between different tremor variables and HAV exposure, along with predictor variables with biological relevance. There were no statistically significant associations between the different tremor variables and cumulative HAV or current exposure. Age was a statistically significant predictor of variation in tremor outcomes for three of the four tremor variables, whereas nicotine use was a statistically significant predictor of either left or right hand or both hands for all four tremor variables. In the present study, there was no evidence of an exposure-response association between HAV exposure and measured postural tremor. Increase in age and nicotine use appeared to be the strongest predictors of tremor.

  • 15. Figueroa Karlström, Eduardo
    et al.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational Medicine.
    Stensson, Olle
    Hansson Mild, Kjell
    Therapeutic staff exposure to magnetic field pulses during TMS/rTMS treatments2006In: Bioelectromagnetics, ISSN 0197-8462, E-ISSN 1521-186X, Vol. 27, no 2, p. 156-158Article in journal (Refereed)
    Abstract [en]

    Transcranial magnetic stimulation or repetitive transcranial magnetic stimulation (TMS/rTMS) is currently being used in treatments of the central nervous system diseases, for instance, depressive states. The principles of localized magnetic stimulation are summarized and the risk and level of occupational field exposure of the therapeutic staff is analyzed with reference to lCNIRP guidelines for pulses below 100 kHz. Measurements and analysis of the occupational exposure to magnetic fields of the staff working with TMS/rTMS are presented.

  • 16.
    Fredrik, Öhberg
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Grip, Helena
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Edström, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Gustavsson, Ola
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Häger, Charlotte
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Gait analysis using a portable motion sensor system: measurements in subjects with hip implant as compared with healthy controls2013In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 38, no suppl 1, p. 99-100Article in journal (Refereed)
    Abstract [en]

    Introduction: There is an increase of age related diseases such as hip joint arthritis, something that is often treated with hip replacement surgery. The aim of this study was to quantify movement function and its effect on quality of life in persons treated with hip implant, in comparison to matched asymptomatic controls.

    Patients/Materials and Methods: This is an ongoing study, and so far, 2 asymptomatic subjects (CTRL, age 50 ± 13 years, BMI 23 ± 2), and 4 subjects with hip implant (HIP, age 51 ± 15 years, BMI 25 ± 3), have been analyzed. The HIP group received their implant 2.6 ± 1.1 years ago and finished their rehabilitation 1.6 ± 1.1 years ago. Hip dysfunction and Osteoarthritis Outcome Score (HOOS) was used to assess the subject's hip function and its associated problems. A functional calibration (flexion/abduction movements) was done and each subject then performed 5 repetitions of gait (approx. 25 left/right gait cycles). Movement was registered with a custom-developed portable motion sensor system, where each sensor consisted of a tri-axial accelerometer and gyroscope. Sensors were placed on pelvis and each thigh and shank. Further calculations were done in MATLAB (v7.12 R2011a, Mathworks). Cosine rotation matrices were extracted by functional sensor-to- segment-calibration and sensor fusion [1], and hip and knee angles were obtained as Euler angles.

    Results: Preliminary results indicated larger range in hip rotation and smaller range of knee flexion during gait in HIP group than in the CTRL group (Fig. 1). HOOS profile (Fig. 2) indicated that hip function during sports (SP) and the general quality of life (QOL) were lower in the HIP group.

    Fig. 1. 

    Mean and SD of hip and knee angle over 15 gait cycles in one HIP subject (blue) as compared with the CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

    Figure optionsFig. 2. 

    HOOS profiles in HIP (blue square) and CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

    Figure options

    Discussion and conclusions: Motion patterns during gait seemed to be negatively affected in subjects with hip implant, even after the rehabilitation program was completed and even though the HOOS profiles indicated a relative good hip function.

    Reference

    • [1]
    • J. Favre, B.M. Jolles, O. Siegrist, K. Aminian
    • Quaternion-based fusion of gyroscopes and accelerometers to improve 3D angle measurement

  • 17. Gerhardsson, Lars
    et al.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Quantitative neurosensory findings, symptoms and signs in young vibration exposed workers2013In: Journal of Occupational Medicine and Toxicology, ISSN 1745-6673, E-ISSN 1745-6673, Vol. 8, p. 8-Article in journal (Refereed)
    Abstract [en]

    Background: Long-term exposure to hand-held vibrating tools may cause the hand arm vibration syndrome (HAVS) including vibration induced white fingers and sensorineural symptoms. The aim was to study early neurosensory effects by quantitative vibrotactile and monofilament tests in young workers with hand-held vibration exposure.

    Methods: This cross-sectional study consisted of 142 young, male machine shop and construction workers with hand-held exposure to vibrating tools. They were compared with 41 non-vibration exposed subjects of the same age-group. All participants passed a structured interview, answered several questionnaires and had a physical examination including the determination of vibrotactile perception thresholds (VPTs) at two frequencies (31.5 and 125 Hz) and Semmes Weinstein's Monofilament test.

    Results: In the vibration exposed group 8% of the workers reported episodes of tingling sensations and 10% numbness in their fingers. Approximately 5-10% of the exposed population displayed abnormal results on monofilament tests. The vibrotactile testing showed significantly increased VPTs for 125 Hz in dig II bilaterally (right hand, p = 0.01; left hand, p = 0.024) in the vibration exposed group. A multiple regression analysis (VPT - dependent variable; age, height, examiner and five different vibration dose calculations - predictor variables) in dig II bilaterally showed rather low R-2-values. None of the explanatory variables including five separately calculated vibration doses were included in the models, neither for the total vibration exposed group, nor for the highest exposed quartile. A logistic multiple regression analysis (result of monofilament testing - dependent variable; age, height, examiner and five vibration dose calculations - predictor variables) of the results of monofilament testing in dig II bilaterally gave a similar outcome. None of the independent variables including five calculated vibration doses were included in the models neither for the total exposed group nor for the highest exposed quartile.

    Conclusion: In spite of the fairly short vibration exposure, a tendency to raised VPTs as well as pathologic monofilament test results was observed. Thus, early neurophysiologic symptoms and signs of vibration exposure may appear after short-term exposure also in young workers.

  • 18. Gerhardsson, Lars
    et al.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Lunsdström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    NEUROPHYSIOLOGIC SYMPTOMS AND VIBRATION PERCEPTION THRESHOLDSIN YOUNG VIBRATION-ExpOSED WORKERS: A FOLLOW-UP STUDY2011In: Canadian Acoustics, ISSN 0711-6659, E-ISSN 2291-1391, Vol. 39, no 2, p. 16-17Article in journal (Refereed)
    Abstract [en]

    Vibration exposure may cause the hand-arm vibration syndrome (HAVS), including digital vasospasms (vibration white fingers; VWF), sensorineural symptoms and/or muscular weakness and fatigue (Gemne, 1997). Neurophysiologic symptoms include numbness and/or tingling, impaired touch sensitivity, impaired manual dexterity and reduced grip strength in the hands. The Stockholm Workshop Scale is commonly used for sensorineural (SN) staging (OSN - 3 SN). Sensorineural symptoms of this in combination with difficulties in handling small objects may interfere both with the workers social- and work-related activities (Sakakibara et al., 2005).

  • 19.
    Grip, Helena
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Häger, Charlotte G.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Section of Physiotherapy.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Öhberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Does the Femoral Head Size in Hip Arthroplasty Influence Lower Body Movements during Squats, Gait and Stair Walking?: A Clinical Pilot Study Based on Wearable Motion Sensors2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 14, article id 3240Article in journal (Refereed)
    Abstract [en]

    A hip prosthesis design with larger femoral head size may improve functional outcomes compared to the conventional total hip arthroplasty (THA) design. Our aim was to compare the range of motion (RoM) in lower body joints during squats, gait and stair walking using a wearable movement analysis system based on inertial measurement units (IMUs) in three age-matched male groups: 6 males with a conventional THA (THAC), 9 with a large femoral head (LFH) design, and 8 hip- and knee-asymptomatic controls (CTRL). We hypothesized that the LFH design would allow a greater hip RoM, providing movement patterns more like CTRL, and a larger side difference in hip RoM in THAC when compared to LFH and controls. IMUs were attached to the pelvis, thighs and shanks during five trials of squats, gait, and stair ascending/descending performed at self-selected speed. THAC and LFH participants completed the Hip dysfunction and Osteoarthritis Outcome Score (HOOS). The results showed a larger hip RoM during squats in LFH compared to THAC. Side differences in LFH and THAC groups (operated vs. non-operated side) indicated that movement function was not fully recovered in either group, further corroborated by non-maximal mean HOOS scores (LFH: 83 +/- 13, THAC: 84 +/- 19 groups, vs. normal function 100). The IMU system may have the potential to enhance clinical movement evaluations as an adjunct to clinical scales.

  • 20. Hagberg, Mats
    et al.
    Burström, Lage
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Incidence of Raynaud's phenomenon in relation to hand-arm vibration exposure among male workers at an engineering plant a cohort study.2008In: Journal of occupational medicine and toxicology (London, England), ISSN 1745-6673, p. 3-13Article in journal (Refereed)
    Abstract [en]

    ABSTRACT: BACKGROUND: The objective of this study was to assess the incidence of Raynaud's phenomenon in relation to hand-arm vibration exposure in a cohort consisting of male office and manual workers. METHODS: The baseline population consisted of 94 office and 147 manual workers at an engineering plant. Raynaud's phenomenon (RP) was assessed at baseline and at follow up (at 5, 10 and 15 years). A retrospective and a prospective cohort analysis of data were done. Hand-arm vibration exposure dose was defined as the product of exposure duration and the weighted hand-arm vibration exposure value according to ISO 5349-1. RESULTS: The retrospective/prospective incidence of Raynaud's phenomenon was 16/14 per 1000 exposure years among exposed and 2.4/5.0 per 1000 years among the not exposed. The retrospective dose response curve based on 4 dose classes showed that class 2, 3 and 4 had similar response and showed higher incidence than the not-exposed. The dose with RP response to hand-arm vibration corresponded to a 10 year A(8) value between 0.4-1.0 m/s2. CONCLUSION: The results indicate that the EU directive on an action value for hand-arm vibration of 2.5 m/s2 is not too low. Rather, it suggests that employers should take on actions even at exposure values of 1 m/s2A(8).

  • 21.
    Hansson Mild, Kjell
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Wilén, Jonna
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Non-Ionizing Radiation in Swedish Health CareExposure and Safety Aspects2019In: International Journal of Environmental Research and Public Health, ISSN 1661-7827, E-ISSN 1660-4601, Vol. 16, no 7, article id 1186Article in journal (Refereed)
    Abstract [en]

    The main aim of the study was to identify and describe methods using non-ionizing radiation (NIR) such as electromagnetic fields (EMF) and optical radiation in Swedish health care. By examining anticipated exposure levels and by identifying possible health hazards we also aimed to recognize knowledge gaps in the field. NIR is mainly used in health care for diagnosis and therapy. Three applications were identified where acute effects cannot be ruled out: magnetic resonance imaging (MRI), transcranial magnetic stimulation (TMS) and electrosurgery. When using optical radiation, such as class 3 and 4 lasers for therapy or surgical procedures and ultra-violet light for therapy, acute effects such as unintentional burns, photo reactions, erythema and effects on the eyes need to be avoided. There is a need for more knowledge regarding long-term effects of MRI as well as on the combination of different NIR exposures. Based on literature and after consulting staff we conclude that the health care professionals' knowledge about the risks and safety measures should be improved and that there is a need for clear, evidence-based information from reliable sources, and it should be obvious to the user which source to address.

  • 22.
    Hedlund, Mattias
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Lindström, Britta
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Sojka, Peter
    Department of Health Sciences, Mid-Sweden University, Östersund, Sweden.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Is better preservation of eccentric strength after stroke due to altered prefrontal function?2016In: Neurocase, ISSN 1355-4794, E-ISSN 1465-3656, Vol. 22, no 2, p. 229-242Article in journal (Refereed)
    Abstract [en]

    Ventrolateral prefrontal cortex (VLPFC) is part of a network that exerts inhibitory control over the motor cortex (MC). Recently, we demonstrated that VLPFC was more activated during imagined maximum eccentric than during imagined concentric contractions in healthy participants. This was accompanied with lower activation levels within motor regions during imagined eccentric contractions. The aim was to test a novel hypothesis of an involvement of VLPFC in contraction mode-specific modulation of force. Functional magnetic resonance imaging was used to examine differences in VLPFC and motor regions during the concentric and the eccentric phases of imagined maximum contractions in a selected sample of subjects with stroke (n = 4). The subjects were included as they exhibited disturbed modulation of force. The previously demonstrated pattern within VLPFC was evident only on the contralesional hemisphere. On the ipsilesional hemisphere, the recruitment in VLPFC was similar for both modes of contractions. The findings support a hypothesis of the involvement of VLPFC in contraction mode-specific modulation of maximum force production. A disturbance of this system might underlie the lack of contraction mode-specific modulation commonly found among stroke subjects, often expressed as an increased ratio between eccentric and concentric strength.

  • 23.
    Hedlund, Mattias
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Sojka, Peter
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindström, Britta
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Insufficient loading in stroke subjects during conventional resistance training2012In: Advances in Physiotherapy, ISSN 1403-8196, E-ISSN 1651-1948, Vol. 14, no 1, p. 18-28Article in journal (Refereed)
  • 24.
    Hedlund, Mattias
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Sojka, Peter
    Department of Health Sciences, Mid-Sweden University, Östersund, Sweden.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindström, Britta
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Torque-angle relationship are better preserved during eccentric compared to concentric contractions in patients with stroke2012In: Isokinetics and exercise science, ISSN 0959-3020, E-ISSN 1878-5913, Vol. 20, no 2, p. 129-140Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to compare the effect of isokinetic contraction mode and velocity on the torque-angle relationship during maximum voluntary elbow flexion in patients with stroke, age-matched healthy subjects and young subjects. To eliminate the effect of torque amplitude differences between subjects and groups, the torque values throughout the ROM were individually normalized to the peak value for each contraction velocity. The results show that in stroke patients the normalized torque angle relationship during the eccentric contractions was better preserved than during concentric contractions. Specifically, during eccentric contractions, stroke patients exhibited a torque-angle relationship that was closer to normal as the test velocity increased. The opposite trend could be seen in concentric contractions where the torque-angle relationship became more divergent from normal with a rise in the velocity. The torque-angle relationships were essentially the same for the control groups, irrespective of contraction mode or velocity. These findings may have significance for loading patterns of resistance training exercises used with stroke patients as such exercises normally are biomechanically designed for normal torque angle relationships. In clinical practice, these findings may partly explain why the strength increases due to resistance training are limited for patients with stroke.   

  • 25.
    Järvholm, Bengt
    et al.
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Malchau, Henrik
    Rehn, Börje
    Vingård, Eva
    Osteoarthritis in the hip and whole-body vibration in heavy vehicles.2004In: Int Arch Occup Environ Health, ISSN 0340-0131, Vol. 77, no 6, p. 424-6Article in journal (Refereed)
  • 26.
    Karlsson, Björn-Markus
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Lindkvist, Marie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lindkvist, Markus
    Karlsson, Marcus
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Håkansson, Stellan
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Wiklund, Urban
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    van den Berg, Johannes
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Sound and vibration: effects on infants' heart rate and heart rate variability during neonatal transport2012In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 101, no 2, p. 148-154Article in journal (Refereed)
    Abstract [en]

    Aim: To measure the effect of sound and whole-body vibration on infants' heart rate and heart rate variability during ground and air ambulance transport.

    Methods: Sixteen infants were transported by air ambulance with ground ambulance transport to and from the airports. Whole-body vibration and sound levels were recorded and heart parameters were obtained by ECG signal.

    Results: Sound and whole-body vibration levels exceeded the recommended limits. Mean whole-body vibration and sound levels were 0.19m/s(2) and 73dBA, respectively. Higher whole-body vibration was associated with a lower heart rate (p<0.05), and higher sound level was linked to a higher heart rate (p=0.05). The heart rate variability was significantly higher at the end of the transport than at the beginning (p<0.01). Poorer physiologic status was associated with lower heart rate variability (p<0.001) and a lower heart rate (p<0.01). Infants wearing earmuffs had a lower heart rate (p<0.05).

    Conclusions: Sound and whole-body vibration during neonatal transport exceed recommended levels for adults and sound seem to have a more stressful effect on the infant than vibrations. Infants should wear earmuffs during neonatal transport because of the stress reducing effect.

  • 27.
    Liljelind, Ingrid
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Pettersson, Hans
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Leif
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Wahlström, Jens
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Toomingas, Allan
    Karolinska Institutet, Institute of Environmental Medicine, Unit of Occupational Medicine SE-171 76 Stockholm, Sweden.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Determinants Explaining the Variability of Hand-Transmitted Vibration Emissions From Two Different Work Tasks: Grinding and Cutting Using Angle Grinders2013In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 57, no 8, p. 1065-1077Article in journal (Refereed)
    Abstract [en]

    Background: There are numerous factors including physical, biomechanical, and individual that influence exposure to hand-transmitted vibration (HTV) and cause variability in the exposure measurements. Knowledge of exposure variability and determinants of exposure could be used to improve working conditions. We performed a quasi-experimental study, where operators performed routine work tasks in order to obtain estimates of the variance components and to evaluate the effect of determinants, such as machine–wheel combinations and individual operator characteristics.

    Methods: Two pre-defined simulated work tasks were performed by 11 operators: removal of a weld puddle of mild steel and cutting of a square steel pipe. In both tasks, four angle grinders were used, two running on compressed air and two electrically driven. Two brands of both grinding and cutting wheels were used. Each operator performed both tasks twice in a random order with each grinder and wheel and the time to complete each task was recorded. Vibration emission values were collected and the wheel wear was measured as loss of weight. Operators’ characteristics collected were as follows: age, body height and weight, length and volume of their hands, maximum hand grip force, and length of work experience with grinding machines (years). The tasks were also performed by one operator who used four machines of the same brand. Mixed and random effects models were used in the statistical evaluation.

    Results: The statistical evaluation was performed for grinding and cutting separately and we used a measure referring to the sum of the 1-s r.m.s. average frequency-weighted acceleration over time for completing the work task (a sa). Within each work task, there was a significant effect as a result of the determinants ‘the machine used’, ‘wheel wear’, and ‘time taken to complete the task’. For cutting, ‘the brand of wheel’ used also had a significant effect. More than 90% of the inherent variability in the data was explained by the determinants. The two electrically powered machines had a mean a sa that was 2.6 times higher than the two air-driven machines. For cutting, the effect of the brand of wheel on a sa was ~0.1 times. The a sa increased both with increasing wheel wear and with time taken to complete the work task. However, there were also a number of interaction effects which, to a minor extent, modified the a sa. Only a minor part (1%) of the total variability was attributed to the operator: for cutting, the volume of the hands, maximum grip force, and body weight were significant, while for grinding, it was the maximum grip force. There was no clear difference in a sa between the four copies of the same brand of each machine.

    Conclusions: By including determinants that were attributed to the brand of both machine and wheel used as well as the time taken to complete the work task, we were able to explain >90% of the variability. The dominating determinant was the brand of the machine. Little variability was found between operators, indicating that the overall effect as due to the operator was small.

  • 28.
    Lindahl, Olof
    et al.
    Luleå tekniska universitet.
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Karlsson, Stefan
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Ramser, Kerstin
    Luleå tekniska universitet.
    Från forskningside till kommersiell produkt på marknaden: CMTF, ett framgångsexempel2009In: Medicinteknikdagarna 2009, Svensk förening för medicinsk teknik och fysik , 2009, p. 17-Conference paper (Refereed)
  • 29.
    Lindahl, Olof
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Luleå tekniska universitet.
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Hallberg, Josef
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Luleå tekniska universitet.
    A Triple-Helix model for refining biomedical engineering research into spin-off companies for the health care market2013In: World Congress on Medical Physics and Biomedical Engineering May 26-31, 2012, Beijing, China / [ed] Mian Long, Springer, 2013, p. 2088-2090Conference paper (Refereed)
    Abstract [en]

    Triple-Helix activities at the centre for biomedical engineering and physics (CMTF) have generated growth both in academia at the universities and in the industry in Northern Sweden. Cooperation was built up between the 26 research projects and about 15 established companies in the field of biomedical engineering. The established researcher - owned company for business development of the research results from the CMTF, CMTF Business Development Co Ltd, has so far launched one spin-off company and has 15 new business leads to business develop. The activities have also increased the interest for commercial and entrepreneurship questions among the scientists in the centre. So far a total of seven spin-off companies have resulted from the CMTF-research since the year 2000.

  • 30.
    Lindahl, Olof
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lundström, Ronnie
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Hallberg, Josef
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    A tripple-helix model for refining biomedical engineering research into innovations and spin-off companies2012In: Medicinteknikdagarna 2012, 2012Conference paper (Refereed)
    Abstract [en]

    Triple-Helix activities within the center for biomedical engineering and physics (CMTF) have generated growth in academic research as well as industry in Northern Sweden in the field of biomedical engineering. Currently CMTF holds 26 ongoing research projects involving more than 150 researchers. So far a total of eight spin-off companies have resulted from research in CMTF since the year 2000. A researcher-owned company, CMTF Business Development Co Ltd, has been established for business development of the research results from the CMTF, which so far have launched two spin-off companies and 15 new business leads for business development. The activities have also increased the interest for innovations and entrepreneurship among the scientists in the center.

  • 31.
    Lindahl, Olof
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Hallberg, Josef
    Luleå tekniska universitet.
    CMTF en forskningsorganisation med slutmålet att förädla resultaten till produkter på hälso- och sjukvårdsmarknaden2011Conference paper (Refereed)
  • 32.
    Lindahl, Olof
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Hallberg, Josef
    Luleå tekniska universitet.
    Development of spin-off companies for health care from biomedical research results2011In: European Conference of the International Federation for Medical and Biological Engineering, 14-18 sept, 2011: vol. 5, Budapest, Ungern, 2011Conference paper (Refereed)
  • 33.
    Lindahl, Olof
    et al.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Ramser, Kerstin
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    From biomedical research to spin-off companies for the health care market2010In: The XII Mediterranean Conference on Medical and Biological Engineering and Computing: vol. 29, part 4, Springer, 2010, p. 624-626Conference paper (Refereed)
    Abstract [en]

    Through research at the centre for biomedical engineering and physics (CMTF) seven new companies have been established in Northern Sweden. The activities have generated growth both in academia at the universities and in the industry in Northern Sweden. Cooperation was built up between the 23 research projects and more than 20 established companies in the field of biomedical engineering. A researcher-owned company for business development of the research results from the CMTF has been established, CMTF Business Development Co Ltd, and has launched its first spin-off company in the autumn 2009. It has also increased the interest for commercial and entrepreneurship questions among the scientists in the centre. So far seven spin-off companies have resulted from the CMTF-research.

  • 34.
    Ljungberg, Jessica
    et al.
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Neely, Gregory
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Cognitive performance and subjective experience during combined exposures to whole-body vibration and noise.2004In: International Archives of Occupational and Environmental Health, ISSN 0340-0131, E-ISSN 1432-1246, Vol. 77, no 3, p. 217-221Article in journal (Refereed)
  • 35.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Environmental Medicine. Arbetarskyddsstyrelsen, Forsknigsavdelningen, Tekniska enheten, Umeå.
    Vibration exposure of the glabrous skin of the human hand1985Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    An occupational exposure to hand-arm vibration can cause a complex of neurological, vascular and musculo-skeletal disturbances, known as the 'vibration syndrome'. However, the underlying pathophysiological mechanisms are not at all clear. Early signs of an incipient vibration syndrome are often intermittent disturbances in the cutaneous sensibility of the fingers, i.e. numbness and/or tactile paresthesias. At later stages, a vasoconstrictive phenomenon appears, usually as episodes of finger blanching.

    When using a vibratory tool, all mechanical energy entering the body has to be transmitted through, or absorbed by, the glabrous skin in contact with the handle. Therefore, the aims of this study was to investigate: (i) mechanical

    responses of the skin to vibrations, (ii) the response properties of cutaneous mechanoreceptors to vibrations, and (iii) influences of vibration exposure on touch perception.

    It was found by measuring the mechanical point impedance (0.02-10 kHz) that the skin is easy to make vibrate within the range of 80 to 200 Hz. Within or close to this range are the dominant frequencies of many vibratory tools. Thus, strong mechanical loads, such as compressive and/or tensile strain, can appear in the skin which, in turn, may induce temporary or permanent injuries.

    Recordings of impulses in single mechanoreceptive afferents, while the skin as exposed to vibrations, were obtained using needle electrodes inserted into the median nerve. The 4 types of mechanoreceptive afferents (FA I, FA II, SA I, and SA II) in the glabrous skin exhibited different response characteristics to vibrations. The FA I units were most easily excited at vibratory frequencies between ca 8 and 64 Hz and the FA II units between ca 64 and 400 Hz. The SA units were most sensitive at lower frequencies. At high stimulus amplitudes, such as may occur while using vibratory tools, a considerable overlap existed between the frequency ranges at which the units were exited. Evidence was also provided, that mechanical skin stimuli produced by edges of a vibrating object, compared to flat surfaces, more vigorously excited the FA I and particularly the SA I units. Thus, a marked edge enhancement, essential for tactile gnosis and precision manipulation, seems to exist already within the peripheral nervous system.

    Acure impairment of tactile sensibility caused by vibrations, proved to be due to a reduced sensitivity of the mechanoreceptive afferents. A loss of manual dexterity a*vi an increased risk for accidents may therefore appear, both during and after a vibration exposure.

    Percussive tools, high speed drills and ultrasonic devices are known to generate mechanical energy at frequencies above 1 kHz, i.e. frequencies usually not felt. At these frequencies, it is known that most of the energy, entering the body, is absorbed by the skin. Therefore, it was investigated whether a long-term exposure to high-frequency vibration may have a detrimental effect on the cutaneous sensitivity. One group of dentists and one of therapists, professionally exposed to high-frequency vibrations, were studied with regard to vibrotactile thresholds in their hands. The study showed that deleterious effects on tactile sensibility, at local exposure to high frequency vibration, can not be excluded.

  • 36.
    Lundström, Ronnie
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Baloch, Adnan Noor
    Hagberg, Mats
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Gerhardsson, Lars
    Long-term effect of hand-arm vibration on thermotactile perception thresholds2018In: Journal of Occupational Medicine and Toxicology, ISSN 1745-6673, E-ISSN 1745-6673, Vol. 13, article id 19Article in journal (Refereed)
    Abstract [en]

    Background: Occupational exposure to hand-transmitted vibration (HTV) is known to cause neurological symptoms such as numbness, reduced manual dexterity, grip strength and sensory perception. The purpose of this longitudinal study was to compare thermotactile perception thresholds for cold (TPTC) and warmth (TPTW) among vibration exposed manual workers and unexposed white collar workers during a follow-up period of 16 years to elucidate if long-term vibration exposure is related to a change in TPT over time. Methods: The study group consisted of male workers at a production workshop at which some of them were exposed to HTV. They were investigated in 1992 and followed-up in 2008. All participants were physically examined and performed TPT bilaterally at the middle and distal phalanges of the second finger. Two different vibration exposure dosages were calculated for each individual, i.e. the individual cumulative lifetime dose (mh/s2) or a lifetime 8-h equivalent daily exposure (m/s(2)). Results: A significant mean threshold difference was found for all subjects of about 4-5 degrees C and 1-2 degrees C in TPTW and TPTC, respectively, between follow-up and baseline. No significant mean difference in TPTC between vibration exposed and non-exposed workers at each occasion could be stated to exist. For TPTW a small but significant difference was found for the right index finger only. Age was strongly related to thermotactile perception threshold. The 8-h equivalent exposure level (A (8)) dropped from about 1.3 m/s2 in 1992 to about 0.7 m/s(2) in 2008. Conclusions: A lifetime 8-h equivalent daily exposure to hand-transmitted vibration less than 1.3 m/s(2) does not have a significant effect on thermotactile perception. Age, however, has a significant impact on the change of temperature perception thresholds why this covariate has to be considered when using TPT as a tool for health screening.

  • 37.
    Lundström, Ronnie
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Dahlqvist, Håkan
    Hagberg, Mats
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Vibrotactile and thermal perception and its relation to finger skin thickness2018In: Clinical Neurophysiology Practice, ISSN 2467-981X, Vol. 3, p. 33-39Article in journal (Refereed)
    Abstract [en]

    Objective: Quantitative measurements of vibrotactile and thermotactile perception thresholds (VPT and TPT, respectively) rely on responses from sensory receptors in the skin when mechanical or thermal stimuli are applied to the skin. The objective was to examine if there is a relation between skin thickness (epidermis and dermis) and VPT or TPT.

    Methods: Perception thresholds were measured on the volar side of the fingertip on 148 male subjects, out of which 116 were manual workers exposed to hand-transmitted vibration and 32 were white-collar (office) workers. Skin thickness was measured using a high-frequency ultrasonic derma scanner system.

    Results: The difference in age, perception thresholds and skin thickness between manual and office workers was small and non-significant except for the perception of cold, which was decreased by vibration exposure. Skin thickness for both subgroups was mean 0.57 mm (range 0.25-0.93 mm). Increased age was associated with decreased perception of warmth and vibration. Lifetime cumulative exposure to vibration, but not age, was associated with decreased perception of cold.

    Conclusion: No association (p > .05) was found between finger skin thickness in the range of about 0.1-1 mm and vibration perception threshold for test frequencies from 8 to 500 Hz and thermotactile perception thresholds for warmth and cold. Increasing age was associated with reduced perception of vibration and warmth. Vibration exposure was associated with decreased perception of cold.

    Significance: Skin thickness is a factor that may affect the response from sensory receptors, e.g., due to mechanical attenuation and thermal insulation. Thus, to evaluate perception threshold measurements, it is necessary to know if elevated thresholds can be attributed to skin thickness. No previous studies have measured skin thickness as related to vibrotactile and thermotactile perception thresholds. This study showed no association between skin thickness and vibrotactile perception or thermotactile perception.

  • 38.
    Lundström, Ronnie
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Clinic of Occupational and Environmental Medicine, Sundsvall, Sweden.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Department of Occupational Medicine, Sahlgrenska University Hospital, Göteborg University, Göteborg, Sweden.
    Exposure-response relationship between hand-arm vibration and vibrotactile perception sensitivity1999In: American Journal of Industrial Medicine, ISSN 0271-3586, E-ISSN 1097-0274, Vol. 35, no 5, p. 456-464Article in journal (Refereed)
    Abstract [en]

    Background  The objectives of the study were to examine whether occupational use of vibrating hand-held tools was associated with an impaired vibrotactile perception, whether any exposure-response relationship exists, and whether the different populations of mechanoreceptive afferent units are equally affected.

    Methods  Vibrotactile perception thresholds have been measured at seven frequencies (8–500 Hz) and evaluated among 125 vibration-exposed and 45 non-exposed male employees in a heavy engineering production workshop. Vibration exposure measurements were assessed on tools in accordance with ISO 5349. Vibrotactile perception thresholds have been individually graded in stages and placed in relation to individual vibration exposure.

    Results  The outcome did not reveal a clear relationship between vibration exposure and reduced vibrotactile sensitivity on an individual basis. There was a clear tendency on a group basis towards elevated thresholds when the study population was divided into three exposure categories. A fourfold increase in relative risk of reduced vibrotactile sensitivity for test frequencies above 40 Hz was observed between the highest exposure category compared to the non-exposed.

    Conclusions  It was concluded that reduced tactile sensitivity is related to the degree of vibration exposure but it is not at present possible to delineate an exposure-response relationship.

  • 39.
    Lundström, Ronnie
    et al.
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Hagberg, Mats
    Burström, Lage
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Grading of sensorineural disturbances according to a modified Stockholm workshop scale using self-reports and QST.2008In: International archives of occupational and environmental health, ISSN 1432-1246, Vol. 81, no 5, p. 553-7Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The objective of the study was to apply, on a group of vibration exposed individuals, a proposed modification of the Stockholm Workshop scale for grading of sensorineural disorders by using self-reports and data from objective testing and to compare grading obtained through the two approaches. METHODS: The study group consisted of 126 young persons with different individual levels of hand-transmitted vibration exposures. Effect measurements included a self-administered questionnaire and vibrotactile perception measurements and Purdue Pegboard testing. For grading using self reports three specific questions, believed to be good markers for complaints of intermittent numbness, sensory deficiency, and reduced performance in fine motor tasks, was picked out from the questionnaire. Results from vibrotactile perception and Purdue Pegboard testing were used for grading based on quantitative sensory testing. The sensorineural grading obtained by the two methods was then compared. RESULTS: The outcome showed that about 60% of all individuals within the study group are graded equally by the two methods for grading. The frequency of individuals graded at advanced SN stages were however higher when using QST, predominantly due to more positive cases for the Purdue pegboard test compared with the corresponding outcome from the self reports. CONCLUSION: The proposed modification of the grading scale reduces the in-built progressiveness and allows different combinations of sensorineural symptoms. The two grading methods seem to be somewhat correlated, something which may be considered as encouraging and promising for those who prefer to use, or must use one of the methods for grading. The proposed model for grading using self-reports should, however, be considered more as a conceptual idea for how this may be done. The models should be applied on a larger, more vibration exposed and more symptomatic study group, compared with the present study group, before any far-reaching conclusions can be drawn.

  • 40. Necking, Lars E
    et al.
    Lundborg, Göran
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Thornell, Lars-Eric
    Umeå University, Faculty of Medicine, Integrative Medical Biology, Anatomy.
    Fridén, Jan
    Hand muscle pathology after long-term vibration exposure.2004In: Journal of Hand Surgery-British and European volume, ISSN 0266-7681, Vol. 29, no 5, p. 431-7Article in journal (Refereed)
    Abstract [en]

    The morphology of the abductor pollicis brevis muscle was studied in 20 patients suffering from hand-arm vibration syndrome. The main morphological changes observed were centrally located myonuclei and fibre type grouping (found in all 20 muscle biopsies), angulated muscle fibres (found in 19 biopsies), ring fibres and regenerating fibres (found in 18 biopsies) and fibrosis (found in 17 biopsies). The observed abnormalities are believed to reflect damage to both the muscle fibres and the motor nerve. The changes were related to different vibration exposure parameters. The number of fibres demonstrating centrally located nuclei correlated significantly with the cumulative vibration exposure, while the number of angulated fibres correlated significantly with the total vibration exposure time. This indicates that the vibrating tools may cause direct damage to muscle fibres as well as nerves.

  • 41.
    Olsson, Carl-Johan
    et al.
    Umeå University, Faculty of Social Sciences, Centre for Population Studies (CPS). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Hedlund, Mattias
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Sojka, Peter
    Department of Health Sciences, Mid-Sweden University, Östersund, Sweden.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lindström, Britta
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Increased prefrontal activity and reduced motor cortex activity during imagined eccentric compared to concentric muscle actions2012In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 6, no 255Article in journal (Refereed)
    Abstract [en]

    In this study we used functional magnetic resonance imaging (fMRI) to examine differences in recruited brain regions during the concentric and the eccentric phase of an imagined maximum resistance training task of the elbow flexors in healthy young subjects. The results showed that during the eccentric phase, pre-frontal cortex (BA44) bilaterally was recruited when contrasted to the concentric phase. During the concentric phase, however, the motor and pre-motor cortex (BA 4/6) was recruited when contrasted to the eccentric phase. Interestingly, the brain activity of this region was reduced, when compared to the mean activity of the session, during the eccentric phase. Thus, the neural mechanisms governing imagined concentric and eccentric contractions appear to differ. We propose that the recruitment of the pre-frontal cortex is due to an increased demand of regulating force during the eccentric phase. Moreover, it is possible that the inability to fully activate a muscle during eccentric contractions may partly be explained by a reduction of activity in the motor and pre-motor cortex.

  • 42.
    Pettersson, Hans
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Department of Occupational and Environmental Medicine, University of Gothenburg, Gothenburg, Sweden.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Department of Occupational and Environmental Medicine, Sundsvall Hospital, Sundsvall, Sweden.
    Noise and hand-arm vibration exposure in relation to the risk of hearing loss2012In: Noise & Health, ISSN 1463-1741, E-ISSN 1998-4030, Vol. 14, no 59, p. 159-165Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to examine the possible association of combined exposure of noise and hand-arm vibration (HAV) and the risk of noise-induced hearing loss. Workers in a heavy engineering industry were part of a dynamic cohort. Of these workers, 189 had HAV exposure, and their age and hearing status were recorded in the same year and were, therefore, included in the analysis. Data on HAV duration and acceleration was gathered through questionnaires, observations, and measurements. All available audiograms were categorized into normal and hearing loss. The first exposure variable included the lifetime HAV exposure. The lifetime HAV exposure was multiplied by the acceleration of HAV for the second and third exposure variable. Logistic regression using the Generalized Estimation Equations method was chosen to analyze the data to account for the repeated measurements. The analysis was performed with both continuous exposure variables and with exposure variables grouped into exposure quartiles with hearing loss as an outcome and age as a covariate. With continuous exposure variables, the odds ratio (OR) with a 95% confidence interval (CI) for hearing loss was equal to or greater than one for all exposure variables. When the exposure variables were grouped into quartiles, the OR with a 95% CI was greater than one at the third and fourth quartile. The results show that working with vibrating machines in an environment with noise exposure increases the risk of hearing loss, supporting an association between exposure to noise and HAV, and the noise-induced hearing loss.

  • 43.
    Pettersson, Hans
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Department of Public Health and Community Medicine, University of Gothenburg, Gothenburg, Sweden.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Risk of Hearing Loss Among Workers with Vibration-Induced White Fingers2014In: American Journal of Industrial Medicine, ISSN 0271-3586, E-ISSN 1097-0274, Vol. 57, no 12, p. 1311-1318Article in journal (Refereed)
    Abstract [en]

    Background: We examined the risk of hearing loss for workers who use hand-held vibrating tools with vibration-induced white fingers (VWF) compared to workers without VWF. Methods: Data on 184 participants from a 21-year cohort were gathered with questionnaires and measurements. The effects on hearing status of VWF, hand-arm vibration exposure, smoking habits, age and two-way interactions of these independent variables were examined with binary logistic regression. Analyses were made for the right hand and ear as well as for the hand with VWF and the ear with worse categorized hearing status. Results: Workers with VWF in their right hand had an increased risk of hearing loss (odds ratio 2.2-2.3) in the right ear. Workers with VWF in any hand did not have any increased risk of hearing loss in the ear with worse hearing status. Conclusions: This study supports the hypothesis that VWF increases the risk of hearing loss among workers who use hand-held vibrating tools in a noisy environment. Am. J. Ind. Med. 57:1311-1318, 2014. (c) 2014 Wiley Periodicals, Inc.

  • 44.
    Pettersson, Hans
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    University of Gothenburg, Department of Public Health and Community Medicine, Gothenburg, Sweden.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Risk of hearing loss in relation to vibration-induced white fingers among workers using hand-held vibrating toolsManuscript (preprint) (Other academic)
    Abstract [en]

    Background Vibration-induced white fingers (VWF) may increase the risk of hearing loss among workers using hand-held vibrating machines who are exposed to noise and hand-arm vibrations (HAV). The present study uses a 21-year follow-up cohort of workers who use hand-held vibrating machines. The aim of this study is to examine the risk of hearing loss for workers with and without VWF who use hand-held vibrating tools.

    Methods All 184 participants used hand-held vibrating machines and were part of a Swedish cohort. At each follow-up each participant answered a questionnaire on basic individual data, use of hand-held vibrating tools, and VWF symptoms. The VWF symptoms were categorized as with or without VWF. HAV acceleration was measured at each follow-up. Hearing threshold levels from audiometric measurements were categorized as normal hearing and hearing loss. Two exposure estimates were used and divided into two exposure groups: lifetime exposure to HAV (Time) and lifetime exposure to HAV multiplied by acceleration (TimeAcc). To be included in the analysis, each participant had to have hearing status, categorized VWF symptoms, exposure estimates and stated smoking habits measured in the same year for either 1987, 1992, 1997, 2002, or 2008. The relationship between binary outcome of hearing status and the interaction of the explanatory variables, i.e. categorized VWF symptoms, exposure estimates, smoking habits and age, were calculated using binary logistic regression. Because of the repeated measurement of these variables, the Generalized Estimating Equations procedure with a first-order autoregressive correlation structure was used. Three analyses were made for left hand and left ear, right hand and right ear, and hand with worst categorized VWF symptoms and ear with worst categorized hearing status.

    Results In our study, there was an interaction between exposure estimates (Time and TimeAcc) with the variable categorized VWF symptoms in the left hand on the risk of hearing loss in the left ear. Workers with VWF in the left hand had an increased risk of hearing loss in the left ear if they were in the low exposure group (OR 4.7-7.1) but not in the high exposure groups. There was an increased risk of hearing loss in the left ear for workers in the high exposure group without VWF in the left hand (OR 3.3-3.6) but not for workers with VWF. Workers with VWF in their right hand had an increased risk of hearing loss (OR 2.2-2.3) in the right ear compared to workers without VWF. Workers with VWF on the hand with worst categorization according to the Stockholm Workshop Scale (SWS) for the vascular component did not have any increased risk of hearing loss in the ear with worse hearing status.

    Conclusions We found that workers with VWF who are using hand-held vibrating machines had an increased risk of hearing loss compared to workers without VWF. This result supports an association between VWF and an increased risk of hearing loss among workers using hand-held vibrating tools in a noisy environment.

  • 45.
    Rehn, B
    et al.
    Umeå University, Faculty of Medicine, Community Medicine and Rehabilitation, Physiotherapy.
    Nilsson, T
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Lundström, R
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Hagberg, M
    Burström, L
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Occupational and Enviromental Medicine.
    Neck pain combined with arm pain among professional drivers of forest machines and the association with whole-body vibration exposure.2009In: Ergonomics, ISSN 1366-5847, Vol. 52, no 10, p. 1240-7Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to investigate the existence of neck pain and arm pain among professional forest machine drivers and to find out if pain were related to their whole-body vibration (WBV) exposure. A self-administered questionnaire was sent to 529 forest machine drivers in northern Sweden and the response was 63%. Two pain groups were formed; 1) neck pain; 2) neck pain combined with arm pain. From WBV exposure data (recent measurements made according to ISO 2631-1, available information from reports) and from the self-administered questionnaire, 14 various WBV exposure/dose measures were calculated for each driver. The prevalence of neck pain reported both for the previous 12 months and for the previous 7 d was 34% and more than half of them reported neck pain combined with pain in one or both arms. Analysis showed no significant association between neck pain and high WBV exposure; however, cases with neck pain more often experienced shocks and jolts in the vehicle as uncomfortable. There was no significant association between the 14 WBV measures and type of neck pain (neck pain vs. neck pain combined with arm pain). It seems as if characteristics of WBV exposure can explain neither existence nor the type of neck pain amongst professional drivers of forest machines. The logging industry is important for several industrialised countries. Drivers of forest machines frequently report neuromusculoskeletal pain from the neck. The type of neck pain is important for the decision of treatment modality and may be associated with exposure characteristics at work.

  • 46.
    Rehn, Börje
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational Medicine.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Leif
    Umeå University, Faculty of Science and Technology, Mathematical statistics.
    Liljellind, Ingrid
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Järvholm, Bengt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Variation in exposure to whole-body vibration for operators of forwarder vehicles - aspects on measurement strategies and prevention2005In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219, Vol. 35, no 9, p. 831-842Article in journal (Refereed)
    Abstract [en]

    Exposure to whole-body vibration (WBV) may cause health problems, e.g. lumbago. The risk will depend on intensity and duration. Exposure to WBV in vehicles varies due to several factors as the vehicle type, the terrain condition, the driver, the speed etc. To estimate the health risk, the measurement strategy has to consider this variation. Furthermore, to understand the importance of different preventive strategies, the cause of the variation has to be known. The objective of this study was to describe variation in exposure to seated WBV during occupational operation of forwarder vehicles and to investigate sources for variation. WBV was measured in 10 various terrain types for seven forwarders operated by 11 drivers. For each driver there were between four and 35 measurements. The measurement periods varied between 0.2 and 34 min. The vibration total value (av) and total vibration dose value (VDVt) were determined. Results showed that WBV exposure varied considerably and that this variation could result in different conclusions regarding health risk assessments. The highest magnitudes were achieved during travelling activities. During travelling empty, variations in av were significantly dependent upon forwarder model and terrain type. No significant predictor for variation in VDVt was however found for travelling empty. During travelling loaded the forwarder model and operator were the most important predictors for variation in av. Variation in VDVt was also dependent on the forwarder model during travelling loaded.

  • 47.
    Rehn, Börje
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational Medicine.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bergdahl, Ingvar A
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Ahlgren, Chrisitina
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational Medicine.
    From, Carin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Sundelin, Gunnnevi
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational Medicine.
    Järvholm, Bengt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Musculoskeletal symptoms among drivers of all-terrain vehicles2002In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 253, no 1, p. 21-29Article in journal (Refereed)
    Abstract [en]

    The aim of this cross-sectional study was to characterize the risk of experiencing musculoskeletal symptoms in the region of the neck, shoulders and upper and lower back for professional drivers of various categories of all-terrain vehicles and to assess the association between symptoms and duration of exposure to whole-body vibration (WBV) and shock from driving all-terrain vehicles. The study group consisted of 215 drivers of forest machines, 137 drivers of snowmobiles and 79 drivers of snowgroomers and a control group of 167 men randomly selected from the general population. The subjects were all from one of the four most northern counties in Sweden and they were all men. Musculoskeletal symptoms were assessed by use of a standardized questionnaire. In addition, the questionnaire held items about the driving time with all-terrain vehicles and a subjective estimation of exposure to unpleasant movements (shock, jolt, irregular sway). The job strain was measured according to Karasek's demands/control model. The prevalence ratios were adjusted for age, smoking and job strain. Among drivers, significantly increased prevalence ratios within the range of 1∂5–2·9 were revealed for symptoms from the neck–shoulder and thoracic regions during the previous year. None of the driver categories had a statistically significantly increased risk of low back pain. Forest vehicles were those most reported to cause unpleasant movements. In conclusion, drivers of all-terrain vehicles exhibit an increased risk of symptoms of musculoskeletal disorders in the neck–shoulder and thoracic regions. The increased risk is suggested to be related to physical factors such as exposure to whole-body vibration (WBV) and shock, static overload or extreme body postures. However, since symptoms of low back pain were not significantly increased, it appears that factors other than WBV would explain the occurrence of symptoms in the group of all-terrain drivers.

  • 48.
    Rehn, Börje
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Lundström, Ronny
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tor
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Bergdahl, Ingvar
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Ahlgren, Christin
    From, C
    Sundelin, Gunnevi
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
    Järvholm, Bengt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Symptoms of musculoskeletal disorders among drivers of all-terrain vehicles in northern Sweden2005In: Noise and Vibration Worldwide, ISSN 0957-4565, Vol. 36, no 1, p. 13-18Article in journal (Refereed)
  • 49.
    Rehn, Börje
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Olofsson, Bodil
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational Medicine.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Whole-body vibration exposure and non-neutral neck postures during occupational use of all-terrain vehicles.2005In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 49, no 3, p. 267-275Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The purpose of this study was to characterize whole-body vibration (WBV) exposure from various all-terrain vehicles (ATVs) like snowgroomers, snowmobiles and forwarders, and to investigate how frequently the drivers' cervical spine is positioned in a non-neutral rotational position during operation. METHODS: Field measurements of WBV were measured according to the international standard ISO 2631-1 in 19 ATVs. Simultaneous recordings of frequency and duration of rotational neck movements exceeding 15 degrees were achieved through an observational method, PEOflex. RESULTS: The sum of the vectors of frequency-weighted r.m.s. acceleration varied between 0.5 and 3.5 m s(-2), which meant that for most vehicles they exceeded the action value stated by the European Union (0.5 m s(r.m.s.)(-2)). In general, snowmobiles achieved the highest vibration total value. The dominant vibration direction for the snowmobile was the x-axis but the z-axis also had relatively high vibration dose values and maximal transient vibration values. The z-axis was the dominant vibration direction for the snowgroomer and the y-axis for the forwarder. Frequency and duration of non-neutral rotational neck postures were relatively low for all driver categories. CONCLUSIONS: Vibration magnitudes in ATVs are considerably high than the EU's action value and the health guidance caution zones in ISO 2631-1. The dominant vibration direction varies depending on the machine type. Duration and frequency of non-neutral rotational positions do not seem to constitute single ergonomic risk factors for musculoskeletal symptoms in the neck among professional drivers of ATVs. However, synergistic effects with other factors are conceivable.

  • 50. Sandén, Helena
    et al.
    Jonsson, Andreas
    Wallin, B Gunnar
    Burström, Lage
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Lundström, Ronnie
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Nilsson, Tohr
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Hagberg, Mats
    Nerve conduction in relation to vibration exposure: a non-positive cohort study2010In: Journal of Occupational Medicine and Toxicology, ISSN 1745-6673, E-ISSN 1745-6673, Vol. 5, p. 21-Article in journal (Refereed)
    Abstract [en]

    Nerve conduction measurements of peripheral hand nerves revealed no exposure-response association between hand-arm vibration exposure and distal neuropathy of the large myelinated fibers in a cohort of male office and manual workers.

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