Prevalence and associated factors of knee osteoarthritis in a community-based population in Heilongjiang, Northeast China

Few data exist concerning the prevalence of knee OA and associated factors in Northeast China. This study was undertaken to estimate the prevalence of radiographic and symptomatic knee OA among community residents and to elucidate relevant risk factors. Unmatched case-control study was adopted to study risk factors of knee OA. Radiographic OA was evaluated according to the Kellgren and Lawrence grading scheme. Statistical analyses included tests and logistic model regressions. A total of 1,196 people aged 40-84 years participated in the community-based health survey in Northeast China in 2005. Survey participants completed an interviewer-based questionnaire. The standardized prevalence of symptomatic knee OA was 16.05% and it was significantly higher in women than in men (19.87% vs. 11.91%, = 13.76, P < 0.001). There was also an increased tendency with age in both sex (men: x (2) = 29.67, P (trend) < 0.001; women: x (2) = 40.26, P (trend) < 0.001). The prevalence of symptomatic knee OA was significantly higher than that in Beijing and Shantou, while lower than that in Wuchuan county of inner Mongolia with nonsignificant difference. Logistic regressions revealed that age, sex, BMI, and work status might be risk factors for knee OA in urban residents, whereas age, BMI, and smoking habits might be risk factors in rural dwellers. Symptomatic knee OA is extremely common with preponderance for elderly women and constitutes a major public health problem. The findings will be useful to guide the distribution of future health care resources and preventive strategies.