[A cross-sectional population survey of knee osteoarthritis in Taiyuan region].

OBJECTIVE: Osteoarthritis (OA) of the knee is found to be one of the commonest rheumatic disorders. For prevention of knee OA, the risk factors for this condition should first be identified. METHODS: A population sample of 2188 adults aged 35 - 64 years, living in 6-story buildings without elevators, was surveyed from April to August 2005 in the urban of Taiyuan region, north China. Protocol of APLAR-COPCORD Core Questionnaire for identification of risk factors for knee OA was implemented. The positive respondents were examined simultaneously by rheumatologists. Lateral and anterior-posterior non-weight-bearing knee radiographs were arranged. Variables such as sex, age, body mass index (BMI), waist circumference, education level, and smoking et al, were included in binary logistic regression model for further analysis. RESULTS: Prevalence rate of knee pain and knee OA was 13.6% and 10.9% respectively, significantly higher than that in Shantou--in south of China and similar with Beijing--in north of China. Both of these prevalence was significantly higher in women than that in men (18.3% vs. 8.7% and 15.1% vs. 6.3%), and with a tendency of being increased with age. The prevalence rate of knee OA was increased more obviously in people after 40 years old in women and after 45 years old in men. BMI in knee OA group was significantly higher than that in non-knee OA group. Binary logistic regression revealed that age, sex, and BMI were significantly associated with knee OA. Whereas there were no significant association between the other factors such as climbing stairs, waist circumference, time length of occupation service, education level, smoking, as well as religious belief and knee OA. CONCLUSIONS: Geography, aging (aged > 40 years in woman and > 45 years in man, respectively), female, and overweight (BMI > or = 24 kg/m(2)) might be the associated risk factors of knee OA. No association between climbing stairs and knee OA was found. Prevention of knee OA should be initiated before the middle-aged, especially in female. Controlling body weight and avoiding obesity are important in preventing knee OA.