Knee pain in middle age and its relationship to occupational work load and psychosocial factors.

In a sample of 574, 55-year-old residents of Malmö, Sweden, the occurrence of knee pain and its relationship with some predisposing factors were analyzed. The prevalence of knee pain was 10%. One percent (men only) had roentgenographic signs of gonarthrosis. Women with knee pain more often had varus knees, but patellofemoral tenderness was more frequent in valgus knees in both men and women. Men with knee pain were on average heavier than those without knee pain. Men and women with knee pain had been less successful in a childhood intelligence test, had a briefer education, were less satisfied with their working conditions, and had jobs with heavier physical demands than the average. The average income was also lower among subjects with knee pain. However, there was an interaction between the measured variables so that in a stepwise logistic regression analysis only two variables, body weight and job satisfaction, remained independent in men; in women, none of the variables was independent.