Pain-Free Living

The Link Between Obesity & Arthritis

By JoAnn Stevelos, MS MPH

It’s no secret that people with obesity have an increased risk of arthritis and arthritis pain. Even a few extra pounds can stress the joints and increase inflammation. Obesity in some cases can increase the risk of being diagnosed with rheumatoid arthritis, and, in most cases, obesity makes arthritis pain worse.

The Centers for Disease Control and Prevention (CDC) report 45% of adults with obesity have physical activity limitations due to arthritis that may prevent them from exercising regularly. The Behavioral Risk Factor Surveillance System showed that on average, obesity among adults with arthritis is 54% higher than among adults without arthritis. Because arthritis limits the types of physical activity in which you can engage, people with both obesity and arthritis may have difficulty maintaining a healthy weight. However, researchers have found that losing even a few pounds through low-impact physical activity and small changes in diet can help relieve pressure on the joints, thus helping with pain management.

As researchers work to understand the relationship between arthritis and obesity, they already have learned that:

– attaining a healthier weight by eating healthier foods and moving more can help a person reduce the risk of arthritis;

– losing even a modest amount of weight can reduce arthritis pain;

– preventing weight gain in children can prevent the development of arthritis; and

– maintaining a healthy weight can benefit joints already affected by arthritis.

Obesity & osteoarthritis

Osteoarthritis (OA) also is known as “wear and tear” arthritis. It affects approximately 27 million Americans. OA is caused by the breakdown or gradual wearing away of cartilage, the connective tissue that covers the ends of bones and joints. The joints affected have lost the smooth cover that helps the bones move easily against each other. Without the covering, the surface of the bone frays, making motion painful. Typically, cartilage breakdowns are a result of aging, injury or obesity. Some people have family history of OA.

What is OA’s link to obesity? When a joint has the added pressure of more weight, it becomes stressed and is more likely to suffer wear and tear. The joints most affected are weight-bearing joints such as knees and hips. Let’s say a person is 40 pounds over his or her ideal weight. What effect would this have on his or her knees? Because every pound of excess weight exerts four pounds of extra pressure, a person who is 40 pounds overweight would have 160 pounds of extra pressure on the knees. This extra pressure accelerates wear and tear on the joint and can cause osteoarthritis.

Fat itself also may cause arthritic flare ups and pain, especially in the hands. Fat is an active tissue that creates and releases chemicals that can inflame joints. The chemical adipokines are cytokines (cell signaling proteins) that are secreted by fat tissue. Researchers suspect  adipokines limit the blood flow to the joint and interfere with cartilage health. Understanding the relationship between weight and arthritis pain may motivate some people with OA to make achieving a healthy weight a priority.

Obesity & rheumatoid arthritis

Rheumatoid arthritis (RA) affects 1.5 million Americans. RA is an autoimmune disease in which the body’s immune system attacks its own joint tissue. When the body is under attack, the joints become inflamed, and this can lead to joint erosion and pain.

Many types of cytokines, like the adipokines in fat that contribute to OA, are released by fat tissue. Researchers are working to identify them and understand the specific effects of each kind. The cytokines that affect people with RA affect not only the joints, but also the cardiovascular system. Two cytokines released in fat are of particular concern for people with RA: tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1). They are the main culprits that cause swelling and pain throughout the body. Like people with OA, those with RA will benefit from reducing the amount of their body fat to lower or minimize painful swelling of the joints.

Obesity & juvenile arthritis

 While arthritis affects mostly adults, children who are obese also can develop arthritis due to excessive weight and pressure on growing joints and bones. However, juvenile arthritis is difficult to define, since there is much disagreement among experts about the specific symptoms, how long they must last before a diagnosis can be made and how the condition should be classified. Most experts agree that a common form of Juvenile Rheumatoid arthritis (JRA) is present when the child is younger than 16 years, has at least six weeks of arthritis symptoms and has no other type of childhood arthritis. Because of conflicting definitions by experts, it also is difficult to know how many children have juvenile arthritis. A 2007 study by the CDC estimates approximately 294,000 U.S. children under age 18 (or one in every 250 children) have been diagnosed with arthritis or another rheumatologic condition.

Like adults, children with excess weight have stressed bones and joints that become susceptible to inflammation and soreness, which may prevent them from enjoying physical activity and participating in sports and outdoor play. Because children’s bones are growing, there is concern obesity can cause bone deformity, adding complications. It is important that caregivers work with their children’s pediatricians to prevent excess weight gain and to maintain a healthy weight. For those children who have obesity, just as with adults, losing even a few pounds can make a difference in the amount of pressure on weight-bearing joints.

Conclusion

Unfortunately, the projected statistics for arthritis are not improving. The CDC estimates that by 2030, the number of adults living with arthritis will increase to nearly 67 million, or 25% of the adult population. These numbers are conservative and do not take into account the number of osteoarthritis cases related to obesity not yet diagnosed. To enjoy a high quality of life and spirit, we must take steps now to make healthy eating and physical activity a priority in our lives to reduce the effects of arthritis.

Last Reviewed October 24, 2015

JoAnn Stevelos, MS MPH, is a public health professional and health writer. She is director of research and evaluation for the Alliance for a Healthier Generation Healthy Schools Program. This article does not necessarily reflect the views of the Alliance for a Healthier Generation.

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