[Cartilage/chondrocyte research and osteoarthritis. Epidemiological studies on osteoarthritis:design and findings.]

Several population-based studies on osteoarthritis(OA)have been conducted, and its risk factors have been examined. Other prospective studies on knee OA recruited individuals with OA and those without but highly at risk of OA. Osteoarthritis Initiative(OAI)in the United States is one of these studies that aimed to identify biochemical, genetic, and imaging biomarkers for the onset and progression of knee OA. In OAI, a total of 4,796 male and female participants aged 45-79 years at baseline have been followed since 2004. OAI is accumulating data that include participants' knee symptoms, health status, physical examination, physical performance, knee radiographs, knee magnetic resonance images, and biospecimens. Clinical data, images, and image assessments are publically available. Japanese researchers can also utilize these resources for their research.