Primary osteoarthrosis of the knee in men and women as a result of lifelong physical load from work

Objectives This study investigated the effect of lifelong physical load Fro m work on the development of knee osteoarthrosis (OA) leading to prosthetic surgery among men and women. Methods In a population-based case-referent study, men and women (N=625) wh o had had prosthetic surgery due to primary tibiofemoral OA were compared w ith referents (N=548) as to job titles and exposure to physical load in occ upational work, housework, and leisure-time activities from 15 to 50 years of age. Results Male forestry and construction workers, and both male and female fa rmers ran the highest risk of knee OA. The men had considerably higher expo sure to lifting at work, and also to jumps and vibration, than the women. A mong the men there was an association between lifting at work [odds ratio ( OR) 3.0, 95% confidence interval (95% CI) 1.6-5.5], squatting or knee bendi ng (OR 2.9, 95% CI 1.7-4.9), kneeling (OR 2.1, 95% CI 1.4-3.3), and jumping (OR 2.7, 95% CI 1.7-4.1) with knee OA. Exposure to physically demanding ta sks at home, such as taking care of an elderly or handicapped person, was a ssociated with knee OA among the women (OR 2.2, 95% CI 1.3-3.6). Conclusions Working as a farmer or as a construction worker could be associ ated with the development of knee OA and lead to prosthetic surgery. Men an d women differ in the quality and quantity of reported physical load and al so in the strength of the risk estimates. A reduction of high physical load at work and at home could probably lower the risk of knee OA later in life .