Clinical review Recent advances Rheumatology

Diet Cross sectional studies and studies of longitudinal cohorts have shown that obesity increases the risk of osteoarthritis of the knee in both men and women, primarily by increasing forces across the knee. An imbalance of growth factors affecting the cartilage and underlying bone may also contribute. Weight loss reduces symptoms as well as improving functional ability. High vitamin C intake is associated with a threefold reduction in progression of osteoarthritis of the knee. Progression of osteoarthritis of the knee and hip is faster in people with lower vitamin D concentrations. 6 However, as yet there is no evidence that vitamin supplementation improves symptoms.