The relationship between body mass index and osteoarthritis for single and multi-site osteoarthritis of the hand, hip, or knee: findings from the CLSA.

Apparent associations between hand OA and BMI may be explained by concurrent OA at other joint sites. Recognizing that OA is a multi-joint disease is crucial for studies of the associations of adiposity with OA in a particular joint, especially the hand. The association between knee OA and BMI appears to be distinct from those for OA at other joint sites.