How does obesity predispose to Osteoarthritis?
Obesity is a risk factor for OA development for two reasons: (1) increased loads, especially over lower-extremity joints, and (2) activation of proinflammatory cytokines. Studies of the knee show that the risk of knee OA increases by 36% for every 5 kg of weight gain. Conversely, it decreases by 50% for every 5 kg of weight loss in obese patients. Adipose tissue may serve as a source of proinflammatory cytokines, such as leptin, adiponectin, resistin, interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-α that can further contribute to joint damage, even in non-weight-bearing joints. This may explain the increased risk for OA in women who have a higher percentage of adipose tissue and the association between obesity and non-weight-bearing DIP joints of the hands. The evidence for an association between obesity and OA is strongest for knee and hand OA.
