Risk of hearing loss in relation to vibration-induced white fingers among workers using hand-held vibrating tools
(English)Manuscript (preprint) (Other academic)
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.
Hand-arm vibration, noise, vibration, combined exposure
Environmental Health and Occupational Health
Research subject Occupational and Environmental Medicine
IdentifiersURN: urn:nbn:se:umu:diva-64150OAI: oai:DiVA.org:umu-64150DiVA: diva2:589170