Few epidemiologic studies have addressed the exposure-response relationships between work activities and symptomatic knee osteoarthritis (OA). This analysis used data from a national survey and ergonomists' ratings to address this issue.
Interview and knee X-ray data were obtained from the Third National Health and Nutrition Examination Survey. Occupational ratings were obtained using ergonomists. A weighted logistic regression was used.
Among men, a significant exposure-response relationship was found between symptomatic knee OA and kneeling. In both genders, there was a significant trend in heavy lifting and severe symptomatic knee OA. Approximately 20.7% of knee OA can be attributed to kneeling >14% of the workday among men.
The significant exposure-response relationships suggest that modest reductions in certain occupational activities can reduce the burden of knee OA. The study was limited by unvalidated expert ratings. Research is needed to identify hazardous characteristics of work activities and to clarify exposure-response relationships.