Question: How does obesity affect my risk of developing osteoarthritis?
Answer: Obesity is a significant disease within the US population, in the population of many industrialized countries at this time. The way that it causes patients to form osteoarthritis or predisposes patients to osteoarthritis is not exactly known at this time. It is speculated that obesity predisposes a patient to osteoarthritis in two separate ways.
The first is biochemical or biologic in which that a patient's cartilage may not be as healthy due to some other factors that the patient has going on within their body, such as increased or decreased insulin and levels of other hormones.
The other way in which obesity may increase a patient's risk for osteoarthritis is biomechanical or mechanical. It is easy to understand that a patient that is five-foot-two and weighs 310 pounds, their joints may be simply overloaded, and the stresses placed on those joints -- such as their feet, ankles, knees, hips, and spine -- those forces may exceed the forces that nature intended those joints to see and thereby mechanically wear out the cartilage in a hastened fashion.
What we see is that patients that are significantly obese, with a body mass index greater than 35, are at significantly increased risk of developing knee arthritis. Some studies would indicate that this risk of developing knee arthritis is at least five-fold greater than patients that have body weights closer to what is called their ideal body weight, other studies show that this risk is even greater than that.