Is There a Link Between Obesity and Rheumatoid Arthritis?

Researchers still don’t know what causes rheumatoid arthritis (RA), but you are more likely to develop the autoimmune condition if you have certain risk factors, per the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMSD). Some of these, like your genetics (having a family history of the disease) and your sex (about two to three times as many women develop RA as men, per the NIAMSD), are frequently discussed. But another factor on the list is less well known: your body weight.

According to a review published in the journal Scientific Reports, people with a higher body mass index (BMI) in middle age and early adulthood, as well as a higher waist circumference, are more likely to have RA than those with a lower BMI or waist circumference.

Moreover, among people already living with RA, those with obesity—meaning, a BMI of 30 or more—have higher levels of disease activity, and tend to respond worse to treatment, says Jeffrey Sparks, M.D., a rheumatologist at Brigham and Women’s Hospital in Boston.

Extra fat tissue doesn’t just sit passively on our bodies: It actively produces inflammatory molecules in the body, according to the Arthritis Foundation. “Adipose [i.e., fat] tissue has pro-inflammatory properties and can contribute to the secretion of pro-inflammatory cytokines and adipokines [molecules produced by fat cells that promote inflammation in the body] and the activation of inflammatory pathways,” says Elena Myasoedova, M.D., Ph.D., a rheumatologist at the Mayo Clinic, in Rochester, MN. This, she says, “can contribute to RA disease development and progression.”

This matters because inflammation is also a part of rheumatoid arthritis, as the immune cells that mistakenly attack the lining of the joints produce an inflammatory response, which in turn can damage a variety of systems, including the skin, eyes, lungs, heart, and blood vessels.

In addition, people who have obesity usually don’t respond to RA treatments as well as those without obesity, according to a review published in the journal Current Rheumatology Reports. “Obese individuals [with RA] can have higher disease activity requiring stronger treatments, while treatments themselves—such as TNF [tumor necrosis factor] inhibitors—can be less effective,” says Dr. Myasoedova. TNF inhibitors are medications that are used to treat RA; they work by helping to stop inflammation, according to the American College of Rheumatology. While it’s not quite clear why certain TNF inhibitors aren’t as effective in people with obesity, it may be that fat cells attach to the medication in the body, rendering it less effective, according to the Arthritis Foundation.

People with obesity and RA may also be more likely to have other health conditions that they’re managing, says Dr. Myasoedova. This includes heart disease and diabetes, according to the Arthritis Foundation. That, she explains, can make it “more difficult to find medication that the patient will tolerate.”

Lastly, people with RA and obesity may also be less physically active than people who have RA and do not have obesity. That not only thwarts some of the many benefits that come with exercise for people with RA, it can also interfere with your ability to take part in therapeutic activity such as physical or occupational therapy, which can help ease symptoms such as stiffness and joint pain, according to Dr. Myasoedova.

“The association between BMI and risk of RA is particularly prominent in women versus men,” says Dr. Myasoedova. The data is mixed, but the Scientific Reports study, for instance, found that obese women had the highest risk for RA, while a study in Medicine didn’t find a link between obesity and RA risk in men at all. One possible reason for the difference is that there are other hormone- or sex-specific factors that also contribute to the development of RA, say the researchers of the Scientific Reports study, although it’s not clear what these may be.

There’s some evidence that losing weight can also improve the symptoms of RA: According to a study of people with either RA or psoriatic arthritis (another form of inflammatory arthritis), those who lost 10% of their body mass were more likely to experience an improvement in their symptoms. Moreover, among those who lost weight, the number of people who achieved remission jumped from 6% to 63%.

Losing weight isn’t easy, but it is possible. Here are a few safe ways to try.

Cut Calories

Dieting doesn’t have a great track record, with an estimated 80% of people who lose weight with diets failing to keep it off for at least 12 months. But it may be worth a try: a study in the journal Rheumatology showed that when obese people with RA slashed their calories to 1,500 calories or less per day, they lost about 20 pounds at the end of three months and experienced improvements in their symptoms, including joint pain and fatigue. You may want to consult with a nutritionist who has experience working with people with RA and can recommend a diet that’s best for you.

Exercise Regularly

Research shows that people who are successful at keeping weight off usually do moderate-intensity exercise for 60 to 90 minutes a day, says the Centers for Disease Control and Prevention (CDC). That doesn’t have to occur all in one block: You can break your exercise into smaller chunks, like two to three 20- to 30-minute walks, and get the same results, per the CDC. Some good exercises for people with RA include yoga, tai chi, walking, aqua aerobics, bike riding, and strength training, according to the Arthritis Foundation. If you’re new to exercising or picking it up after a long layoff, consider working with a physical therapist or other exercise specialist for help getting started, says Dr. Myasoedova.

Ask About Medications

The development of GLP-1 medications like Wegovy has changed the face of today’s obesity treatments, and while the jury is still out about what role they may play for people with RA, there are some encouraging signs. “The role of GLP 1 receptor agonists in RA is an area of growing research,” says Dr. Myasoedova. While more studies are needed, “there are some promising associations with improved RA disease activity, mostly from small studies,” she says.

Talk to your doctor about the pros and cons of these types of medications.

Consider Surgery

If you have obesity and either haven’t been able to lose weight or keep it off, you may be a candidate for weight-loss surgery, which may include making the stomach smaller or altering the small intestine to reduce the amount of calories that are absorbed by the body, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDKD). Some research has found that people with RA and obesity experienced not only significant weight loss, but also had a better response to their RA medication.

Obesity is one of the risk factors for rheumatoid arthritis. In addition to an increased risk of the autoimmune condition, obesity is also linked to higher levels of disease activity and more resistance to treatments. Talk to your doctor about ways to lose weight safely, including through diet and exercise, or medication or surgery.