There is increasing evidence that musculoskeletal and other soft tissue disorders are widespread in U.S. industries, and evidence is developing that occupational exposures to ergonomic stressors are an important source of these problems. However, epidemiologic research on these problems has been largely limited to cross-sectional studies. The proposed study takes advantage of data collected longitudinally on a population of garment workers. The proposal is for an analysis of the longitudinal data on workers in a large garment manufacturing shop whose cross-sectional symptoms, signs, and ergonomic exposures have already been reported on by the applicant.
The specific aims of this investigation are: (1) to estimate the 24-month cumulative incidence of upper extremity soft tissue disorders as a function of exposure; (2) to estimate the magnitude of the selection bias resulting from symptomatic workers leaving the workplace; (3) to estimate the long-term and short- term persistence of symptoms and signs, and the complementary recovery rates, as a function of exposure; (4) to estimate the reproducibility of findings on physical examination; (5) to estimate the agreement between the results of two-point discrimination testing for median nerve impairment and other indications of carpal tunnel syndrome; (6) to explore the association between upper extremity pain and work pace under a piece-rate wage system; and (7) to evaluate whether there is significant seasonal variation in the ergonomic features of specific garment assembly tasks. The 24-month follow-up investigation (including a survey/re-survey of symptomatic workers) will provide the following data: (a) findings on interview and physical examination for those workers still employed at 24 months from the date of the baseline survey; (b) hours worked and earning in the week of the follow-up survey; and (c) findings on interview and physical examination at 30 months from the date of the baseline survey, for those workers symptomatic at 24 months, with examinations conducted by two investigators for each subject. These data will be analyzed in relation to the intensity of ergonomic exposures previously characterized. Additional observations will be made regarding specific ergonomic features of selected jobs at four occasions during the year corresponding to seasonal changes in garment styles under construction.
