Not just loading and age: the dynamics of osteoarthritis, obesity and inflammation
Body fat is not an inert structure
Obesity is a well recognised risk factor for osteoarthritis (OA).1 It is commonly believed that obesity affects joints through loading. However, there must be additional mechanisms since, for decades, obesity has been known to be a strong risk factor for hand OA. Given that we do not walk on our hands, an effect of obesity through loading of the joints cannot be the whole explanation. An understanding of the potential mechanisms by which obesity affects joints is important for optimising the treatment and prevention of OA.
Work over the past decade using magnetic resonance imaging has enabled the assessment of factors affecting joints across the spectrum of the disease, from normal asymptomatic joints to symptomatic OA.1 This has made it possible to examine the effect of obesity on joints, and to untangle the issue of whether obesity causes OA or whether OA-related pain causes obesity through modification of lifestyle behaviours and consequent weight gain. This work has shown that obesity is a causative factor in the development of OA, with increased weight being associated with early articular cartilage damage, well before symptoms develop.1 Obesity is an important risk factor for OA across a wide range of joints, including hands, back, hip and knee.
Having established the importance…