OSTEOARTHRITIS OF THE HIP AND KNEE AND MECHANICAL OCCUPATIONAL EXPOSURE - A SYSTEMATIC OVERVIEW OF THE EVIDENCE

Objective. To critically examine the epidemiologic evidence linking wo rk related exposure to osteoarthritis (OA) of the hip and knee. Method s. We investigated MEDLINE and EMBASE 1966-1994 with search terms oste oarthritis, osteoarthrosis, arthrosis; risk factors, exposure; occupat ional diseases, agricultural workers' diseases, work. From 123 origina l studies on risk factors for OA; 17 studies were identified as provid ing a comparison group and relating the presence or absence of radiolo gically diagnosed OA to occupational factors. The quality of the metho dology of each study was evaluated independently by 4 reviewers using a standardized protocol. Results, Common methodological problems were encountered in areas such as representativeness, recall of exposure, a nd evaluation of exposure and outcome. These problems often made a cau se-effect relationship difficult to interpret. However, 7 of the 17 st udies met our criteria for good methodological quality. A critical ana lysis of their results led to the following conclusions: (1) A consist ently positive relationship exists between work involving knee bending and knee OA in men (range of odds ratios: 1.4-6). (2) The evidence su ggesting a relationship between knee OA and occupational exposure in w omen is inconclusive. (3) A consistently positive but weak relationshi p exists between work related exposure (i.e., farming in particular) a nd hip OA in men. We felt we could not conclude with confidence that t his relationship is strong due to the potential biases that exist in e ach of these studies. (4) No study attempted to investigate occupation al exposure and hip OA in women. Conclusion. Studies suggest a strong positive relationship between work related knee bending exposure and k nee OA. The evidence between work related exposure, fanning in particu lar, and hip OA is consistently positive but weak.