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BACKGROUND CONTEXT: Degenerative changes due to cervical spondylosis (CS) can detrimentally affect work ability and quality of life yet understanding of how physical exposure affects disease progression is limited.

PURPOSE: To assess the associations between occupational physical exposures and occurrence of surgically treated cervical spondylosis (ST-CS) and early exit from the labour market via disability pension.

STUDY DESIGN/SETTING: Prospective register study with 20 year follow-up period.

PATIENT SAMPLE: Swedish construction workers participating in a national health surveillance project conducted between 1971-1993.

OUTCOME MEASURES: Surgically treated cervical spondylosis (ST-CS) and early labour market exit at a minimum rate of 25% time on disability pension.

METHODS: Associations between occupational physical exposures (job exposure matrix) and subsequent ST-CS (National Hospital in-patient register) and early labour market exit via disability pension (Swedish Social Insurance Agency register) were assessed in a cohort of male construction workers (n=237,699).

RESULTS: A total of 1381 ST-CS cases were present and a 20-year incidence rate of 35.1 cases per 100,000 person years (95% confidence interval (CI) 33.2-36.9). Increased relative risk (RR) for ST-CS was found for workers exposed to non-neutral (RR 1.40, 95% CI 1.15-1.69) and awkward neck postures (1.52, 1.19-1.95), working with the hands above shoulder height (1.30, 1.06-1.60), and high upper extremity loading (1.35, 1.15-1.59). Increased risk was also present for workers who reported frequent neck (3.06, 2.18-4.30) and upper back (3.84, 2.57-5.73) pain in the 12 months prior to survey. Among workers with elevated arm exposure, higher risk was seen in those who also had more frequent neck pain. ST-CS cases took early retirement more often (41.3%) and at a younger age (53 years) than the total study cohort (14.8% and 56 years of age, respectively).

CONCLUSIONS: Occupational exposure to non-neutral neck postures, work with hands above shoulders and high loads born through the upper extremities increased the risk for ST-CS and early retirement due to disability. Decreasing postural and load exposure is salient for primary, secondary, and tertiary prevention of CS. Neck pain was shown to be a prognostic factor for ST-CS, which stresses the importance of acting early and taking preventative action to reduce workplace exposure, and the need for systematic medical check-ups within primary or occupational care to mitigate disease progression and early labour market exit due to disability.

OBJECTIVE: The aim of this study was to assess the association between occupational biomechanical exposures and the occurrence of surgical treatment for subacromial impingement syndrome (SIS).

METHODS: A cohort of 220 295 male constructions workers who participated in a national occupational health surveillance program (1971-1993) were examined prospectively over a 16-year follow-up period (2001-2016) for surgically treated SIS. Worker job title, smoking status, height, weight, and age were registered on health examination. Job titles were mapped to 21 occupational groups based on tasks and training. A job exposure matrix (JEM) was developed with exposure estimates for each occupational group. Surgical cases were determined through linkage with the Swedish national in- and outpatient registers. Poisson regression was used to assess the relative risks (RR) for each biomechanical exposure.

RESULTS: The total incidence rate of surgically treated SIS over the 16-year observation period was 201.1 cases per 100 000 person-years. Increased risk was evident for workers exposed to upper-extremity loading (push/pull/lift) (RR 1.45-2.30), high hand grip force (RR 1.47-2.23), using handheld tools (RR 1.52-2.09), frequent work with hands above shoulders (RR 1.62-2.11), static work (RR 1.77-2.26), and hand-arm vibration (RR 1.78-2.13). There was an increased risk for SIS surgery for all occupational groups (construction trades) compared with white-collar workers (RR 1.56-2.61).

CONCLUSIONS: Occupational upper-extremity load and posture exposures were associated with increased risk for surgical treatment of SIS, which underlines the need for reducing workplace exposures and early symptom detection in highly exposed occupational groups.

OBJECTIVES: The aim was to assess the association between occupational biomechanical exposure and the occurrence of radial nerve entrapment (RNE) in construction workers over a 13-year follow-up period.

METHODS: A cohort of 229 707 male construction workers who participated in a national occupational health surveillance programme (1971-1993) was examined prospectively (2001-2013) for RNE. Height, weight, age, smoking status and job title (construction trade) were obtained on health examination. RNE case status was defined by surgical release of RNE, with data from the Swedish national registry for out-patient surgery records. A job exposure matrix was developed, and biomechanical exposure estimates were assigned according to job title. Highly correlated exposures were summed into biomechanical exposure scores. Negative binomial models were used to estimate the relative risks (RR) (incidence rate ratios) of RNE surgical release for the biomechanical factors and exposure sum scores. Predicted incidence was assessed for each exposure score modelled as a continuous variable to assess exposure-response relationships.

RESULTS: The total incidence rate of surgically treated RNE over the 13-year observation period was 3.53 cases per 100 000 person-years. There were 92 cases with occupational information. Increased risk for RNE was seen in workers with elevated hand-grip forces (RR=1.79, 95% CI 0.97 to 3.28) and exposure to hand-arm vibration (RR=1.47, 95% CI 1.08 to 2.00).

CONCLUSIONS: Occupational exposure to forceful handgrip work and vibration increased the risk for surgical treatment of RNE.

Background: Shoulder disorders are common in the general population, with an annual prevalence up to over 40% per 1000 person-years. One common disorder is subacromial impingement syndrome (SIS), where a narrowing in the subacromial space causes compression of the tendons or bursa by the surrounding tissues. When conservative treatments are not effective, surgical treatments is often the alternative. The aim of the current study was to assess the association between occupational biomechanical exposures and the occurrence of surgically treated SIS in a large construction worker cohort over a 16-year follow-up period. 

Methods: A cohort of 280 747 male construction workers who participated in a national occupational health surveillance program (1971-1993) were examined prospectively (1987-2016) for SIS. SIS case status was defined by primary surgical treatment of diagnosis codes M75.1, M75.4, 726B, or 726C (ICD 10 and Swedish ICD 9 code systems), with data from the Swedish national registry for in- and out-patient surgery records. A job exposure matrix (JEM) was developed and biomechanical exposure estimates were assigned according to job title. Poisson regression models adjusted for age, BMI, smoking and a surgical time factor were used to estimate the relative risks (incidence rate ratios) of surgical treatment for SIS for each biomechanical factor.

Results: There were 1381 cases in the cohort, which corresponded to an incidence rate of surgically treated SIS over the 16-year observation period of 46 cases per 100,000 person years. Increased risk for surgically treated SIS was shown for working with elevated arms (RR=1.27, 95% CI=1.02-1.58), heavy upper arm loads (RR=1.75, 95% CI=1.48-2.08), high grip force (RR=1.64, 95% CI=1.40-1.93), working with hand tools (RR=1.46, 95% CI=1.26-1.70), working with hand tools in a fixed posture (RR=1.28, 95% CI=1.14-1.44), and working with hand-arm vibration (RR=1.30, 95% CI=1.09-1.55).

Conclusions: Working with elevated arms, high arm load, high grip force and vibrating handheld tools may increase the risk for SIS.

Objectives: The aim of this study was to determine the association between occupational biomechanical exposures and occurrence of surgically treated ulnar nerve entrapment (UNE).

Methods: A cohort of 229 689 male construction workers who participated in a national occupational health surveillance program (1971–1993) were examined prospectively over a 13-year case ascertainment period (2001–2013) for surgically treated UNE. Job title (construction trade), smoking status, height, weight and age were recorded on examination. Job titles were merged into occupational groups of workers performing similar work tasks and having similar training. Occupational biomechanical exposure estimates were assigned to each occupational group with a job exposure matrix (JEM) developed for the study. Negative binomial models were used to assess the relative risks for each biomechanical exposure and the sums of highly correlated biomechanical exposures. Surgical treatment of UNE was determined via a linkage with the Swedish Hospital Outpatient Surgery Register.

Results: There were 555 cases of surgically treated UNE within the cohort. Workers exposed to forceful hand-grip factors had a 1.4-fold higher relative risk (95% CI 1.18–1.63) of undergoing surgical treatment for UNE compared to unexposed workers. Occupational groups comprising workers exposed to forceful hand-grip work showed the highest risks for UNE and included concrete workers, floor layers, ground preparatory workers, rock blasters, and sheet-metal workers.

Conclusion: Forceful hand-grip work increases the risk for surgically treated ulnar nerve entrapment.

Background: The aim of this study was to assess the associations between individual and occupational exposure factors and hospitalization for cervical disc disorder (CDD).

Methods: CDD was examined prospectively in a cohort of 278 319 Swedish male construction workers who participated in a national health surveillance program (1971-1993). Job title, smoking status, age, height, and weight were recorded on examination. Case data were obtained through linkage with the Swedish national in-patient hospital registry for the period 1987 – 2016; case status was defined by primary diagnosis code M50.0 (ICD-10) or 722.0, 722.4, or 722.7 (ICD-9). A job exposure matrix was developed and occupational exposure estimates were assigned by job title. Self-reported estimates of pain/discomfort from a subset of 87 500 workers were also linked to the database. Poisson regression models were used to estimate the relative risks (RR) for the biomechanical and self-reported factors with adjustment for smoking status, age, BMI and surgical time period.

Results: There were 562 cases of hospitalization for CDD; the incidence rate was 8.0 cases per 100 000 during the 29-year follow-up period. Smoking status, age, BMI and height were all associated with increased risk (RR 1.21-3.16). Occupational exposure to static work in non-neutral or extreme neck postures, and time spent in awkward postures showed the highest associations with CDD hospitalization (RR = 1.62 – 2.10). Upper arm load and time with arms above shoulders were also associated with increased risk (RR = 1.50 – 1.58). Workers who reported experiencing pain ‘often’ or ‘very often’ during the previous year for any of the neck, shoulder or upper back regions had a 3-fold increase in risk relative to workers reporting no pain.

Conclusions: Occupational non-neutral neck posture was associated with increased risk of hospitalization for CDD. Our data also suggest an exposure-response relationship for self-reported neck pain/discomfort and risk of hospitalization for CDD.

Background: Carpal tunnel syndrome (CTS) is the most common upper extremity nerve entrapment syndrome . The aim of this study was to determine the association between occupational biomechanical exposures and occurrence of surgically treated CTS in construction workers over a 16-year follow-up.

Methods: A cohort of 220 610 male construction workers who participated in a national occupational health surveillance program (1971–1992) were examined prospectively (2001–2016) for surgically treated CTS. Cases were determined via a linkage with the Swedish Hospital Outpatient Register. Job title (construction trade), smoking status, height, weight and age were recorded on examination. Job titles were merged into occupational groups of workers performing similar work tasks and having similar training. Occupational biomechanical exposure estimates were assigned to each occupational group using a job exposure matrix (JEM) developed for the study. Poisson regression models were used to assess the relative risks for each biomechanical exposure. Relative risks were adjusted for age, surgical time period, BMI, and smoking status at first examination.

Results: There were 4048 cases of surgically treated CTS within the cohort which represented an incidence rate of 134 cases per 100 000 person years. Workers exposed to medium and high forceful handgrip factors had relative risks of 1.3 (95% CI 1.16-1.38) and 1.6 (95% CI 1.50-1.77), respectively, of undergoing surgical treatment for CTS compared to low exposed workers. Workers exposed to medium and high exposure to hand-arm vibration had relative risks of 1.3 (95% CI 1.19-1.34) and 1.2 (95% CI 1.07-1.28), respectively, of undergoing surgical treatment for CTS compared to low exposed workers.

Conclusions: In conclusion, forceful hand-grip work and exposure to hand-arm vibration increased the risk for surgically treated carpal tunnel syndrome.

Background: The literature on occupational risk factors for ulnar nerve entrapment (UNE), also called cubital tunnel syndrome is sparse.

Objectives: The aim was study the association between occupational biomechanical exposures and UNE.

Methods: The occurrence of UNE was examined prospectively in a cohort of 229 689 Swedish male construction workers who participated in a nation-wide occupational health surveillance program between 1971 and 1996. UNE case status was defined on the basis of a surgical release of ulnar nerve entrapment; case data were obtained from a national outpatient database for a 13 year observation period (2001-2013). Individual risk factors considered were smoking status, BMI and age. Biomechanical exposure estimates were assigned at the occupational group level using a job exposure matrix developed specifically for the study and included 10 ergonomic (force/posture/repetition) and 2 hand-arm vibration exposure parameters determined a priori to be relevant to UNE. Relative risks (RR) for all biomechanical factors were modelled using negative binomial regression analyses and adjusted for age, smoking habits and BMI.

Results: There were 555 cases of surgically treated UNE in the cohort and the average annual incidence was 19.2 cases per 100,000 person-years. Smoking status (ever vs. never smoker RR=1.28, 95% CI=1.07-1.54) and BMI (≥25 kg/m2 vs. < 25 kg/m2 RR=1.60 , 95% CI=1.34-1.91) were associated with increased risk of UNE. Increased grip force (RR=1.54, 95% CI =1.24-1.92), hand-Arm-vibration (RR=1.35, 95% CI=1.07-1.71) upper extremity load (RR=1.63, 95% CI=1.30-1.92), and increased frequency of hand tool use (RR =1.37, 95% CI=1.09-1.71), elbow flexion and extension (RR=1.36, 95% CI=1.10-1.68), and static work (RR=1.36, 95% CI=1.12-1.65) were also associated with increased risk of UNE.

Discussion and Conclusions: Our findings demonstrate that multiple biomechanical factors were associated with increased risk of UNE. Many of the identified risk factors involved elevated hand grip force (grip force, upper extremity load, and frequency of hand tool use and hand-arm vibration) which may indicate it is a key etiological aspect of UNE.