Osteoarthritis (OA) is the most common form of arthritis. Most data on the prevalence of OA have been generated from Caucasian populations. Despite evidence from clinical studies that hip OA is rare in Asians, OA has not been well-studied in any Asian populations, and rates of OA in other joints are unknown. In N.I.H. sponsored workshops on OA in 1985 and again in 1994, consensus statements called for cross-national studies involving non-Caucasian populations. None has been undertaken. The first goal of this project is to evaluate whether the prevalences of hip, hand, and knee OA are different among Chinese 60 years and over living in Beijing than among Caucasians of comparable age from the U.S. The second goal is to evaluate whether Caucasian and Chinese populations have different risk factor profiles and to examine factors associated with prevalent disease in Chinese. To accomplish these goals, the investigators propose the following specific aims: 1. To identify a population-based cohort of Chinese men and women 60 years and over in Beijing. 2. To obtain arthritis histories, examinations, knee, hip, and hand x-rays and assess risk factors on members of the Beijing cohort. 3. To have x-rays from China read with x-rays from the Framingham Osteoarthritis Study (knees, hands), the NHANES I (hips) and III (hands) and the Study on Osteoporotic Fractures (hips). 4. To evaluate the prevalence of OA in each joint defined in several different ways (symptomatic disease, x-ray disease only) and compare this to comparably defined prevalence in the Framingham, NHANES I and III and SOF studies. 5. To perform analyses comparing the prevalence of risk factors for OA in Chinese and Caucasians free of OA at specific joints, and to evaluate the association of established and new risk factors with prevalent OA in Chinese. The investigators point out that this study will provide the first population-based prevalence rate data on OA in an Asian population and, because of its use of data from comparable Caucasian populations, will permit an assessment of whether the prevalence rates in Chinese and Caucasians differ. In addition to evaluating the comparative prevalence of known risk factors such as weight, novel risk factors will be tested including historical squatting, joint geometry and thickness, and serum vitamin C. Although a prevalence study, the survey in Beijing will be large enough to serve as the baseline for a later study of knee and hand OA incidence rates in women.
