According to the Centers for Disease Control and Prevention, obesity is a major risk factor for osteoarthritis, a degenerative joint disease that affects more than a third of adults over the age of 60. So, for people who are obese—meaning they have a body mass index (BMI) of 30 or above—there is a statistically higher likelihood that they will develop osteoarthritis.

Why is obesity a risk factor for osteoarthritis?

When discussing knee osteoarthritis, one might assume that the added load caused by obesity is what causes the joint degeneration present in knee osteoarthritis – but that would be only partially correct. Studies show that obese people also have more arthritic changes in their neck and in the joints of their fingers. The current explanation is that fat (particularly abdominal fat, a.k.a the beer belly) changes the metabolism of the whole body increasing chances of osteoarthritis.

Can losing weight decrease knee joint deterioration?

Although it’s established that obesity can put someone at higher risk for knee joint deterioration, the question is whether the opposite is also true. Can losing weight help decrease the rate of knee joint deterioration? And, if so, how much weight must one lose?

An MRI study done by scientists at the University of California, San Francisco aimed to explore these questions and found that obese people who lose a substantial amount of weight can significantly slow the degeneration of their knee cartilage.

How California scientists concluded that losing weight can decrease knee joint deterioration

The MRI study, mentioned above, investigated the association between different degrees of weight loss and the progression of knee cartilage degeneration in 506 overweight and obese patients from the Osteoarthritis Initiative, a nationwide research study focused on the prevention and treatment of knee osteoarthritis. The patients either had mild to moderate osteoarthritis or risk factors for the disease. They were divided into three groups: a control group who did not lose weight, a second group who lost a little weight, and a third group who lost more than 10 percent of their body weight. The researchers then used MRI to quantify knee osteoarthritis.

When the researchers analyzed differences in the quality of cartilage among the three groups over a four-year time span, they found evidence that weight loss has a protective effect against cartilage degeneration and that a larger amount of weight loss is more beneficial.

“Cartilage degenerated a lot slower in the group that lost more than 10 percent of their body weight, especially in the weight-bearing regions of the knee. However, those with 5 to 10 percent weight loss had almost no difference in cartilage degeneration compared to those who didn’t lose weight.”

“Substantial weight loss not only slows knee joint degeneration—it also reduces the risk of developing osteoarthritis. Along with moderate exercise, weight loss is one of the primary interventions against the disease”

“It’s most helpful if these lifestyle interventions take place as early as possible” says the study’s lead author, Alexandra Gersing, (M.D.).

Double trouble – coping with both arthritis and obesity

The catch 22 for overweight people who struggle with arthritic knee pain is the dual barriers preventing them from getting exercise, which in turn increases their likelihood of weight gain and decreased joint function. Therefore, it is crucial to make therapies available that can make exercise possible for people suffering from arthritis and/or obesity.

Therapies such as water aerobics, take much of the weight caused by gravity out of the equation, making movement and exercise more feasible. Alternatively, physical therapy can help patients move better, with less pain, and therefore make it possible for them to do more types of exercise. AposTherapy® both reduces some of the weight from the painful part of the joint and makes daily activities into an exercise. This makes it possible for patients to experience improved function and less pain while doing regular walking and going about daily activities.

The bottom line is that people struggling with obesity and joint pain should not wait until things get worse. Taking a proactive approach to weight loss and joint health pays off in the long run.