s-557 LONGITUDINAL ASSESSMENT OF INDUSTRIAL WORKERS

Numerous investigators have performed cross-sectional studies of upper extremity musculoskeletal disorders (UEMSDs) among industrial workers, and modeled the prevalence of these conditions in relation to potential ergonomic exposures and other covariates. However, prospective studies have been rare for a variety of reasons. Results of a cross-sectional study of UEMSDs based on data collected approximately 5 years ago were published in 1999 (L&o et al., 1999). A subset ofthe workers from this study were available for re-examination approximately 5 years after the frst investigation. The survey tools and clinical examination protocols used in the follow-up examinations were largely identical to the baseline procedures, thus permitting direct comparison of results between rounds. Workers from 2 of the 3 employers in the original study were available for the follow-up investigation. Just over 50 % of available and eligible workers participated in the follow-up examinations (152 out of 267, or 57%). The mean age at follow-up was almost 48 years (standard deviation = 9.5 years). The mean body mass index (BMI) was 28.9 at follow-up, and just over half of the study participants were male (53%). Most subjects were still employed by the same employer, and most were still in the same jobs. The prevalence and severity of upper extremity symptoms declined significantly in most body regions between baseline and follow-up. In contrast, the prevalence of most upper extremity diagnoses (tendinitis and carpal tunnel syndrome based on symptoms, standardized physical examinations, and/or nerve conduction tests) increased slightly, though not significantly. Relative median-minus-ulnar peak latency differences increased slightly, and significantly, between rounds. There are almost no studies for comparison of results. More prospective studies are heeded to better understand the natural history of upper extremity musculoskeletal disorders among workers