BIOMECHANICAL ASPECTS OF OCCUPATION AND OSTEOARTHRITIS OF THE HIP - ACASE-CONTROL STUDY

Objective. Our study was designed to examine the association between b iomechanical aspects of occupation and hip osteoarthritis (OA). Method s. Ninety-nine cases of primary hip OA and 233 controls were recruited from the outpatient clinics of a Department of Veterans Affairs Hospi tal. Subjects were mailed a questionnaire which asked about lifetime p articipation in various occupational and recreational activities, body mass, medical conditions and demographic information. Occupational wo rk load was defined based on the joint compression forces produced by an occupational activity. Activities which produced joint compression forces at least twice body weight were considered heavy. Activities wh ich produced joint compression forces less than body weight were consi dered light, All others were considered intermediate. Based on respons es to the questionnaire, subjects were classified as exposed to heavy, intermediate or light work. Results. Using light work as the referenc e category, subjects in the intermediate work category had 2.0 times a nd those in the heavy work category had 2.4 times the odds of having h ip OA. Logistic regression was used to control for possible confoundin g. After adjusting for cancer, football and obesity at age 40, subject s who performed heavy work for at least 15 years had 2.4 times the odd s of having hip OA compared to subjects who had performed light work. A test for trend in the odds of hip OA with increasing levels of expos ure to heavy work was significant. Conclusion. The biomechanical aspec ts of occupation may contribute to the risk of hip OA.