Obesity. It’s the modern American epidemic that afflicts more than one-third of all U.S. adults. Obesity has been linked to a seemingly endless list of diseases and disorders, including T ype 2 diabetes; heart disease and stroke; cancer of the esophagus, pancreas, colon and rectum, breast, endometrium and kidney; lung diseases such as asthma and obstructive sleep apnea; back pain and other musculoskeletal conditions such as osteoarthritis; reduced fertility; and depression, memory problems and poor quality of life.
And you may be able to add rheumatoid arthritis to that list.
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Rheumatoid arthritis is a chronic autoimmune disease in which the body’s immune system mistakenly goes on the attack against its own healthy tissue. The disease is characterized by the release of proteins, called cytokines, that are responsible for widespread inflammation that damages the joints and other organs.
According to the website arthritis.org, fat, or adipose tissue, also causes inflammation by releasing many of the same inflammatory cytokines that are already overactive in RA, including tumor necrosis factor-alpha, interleukin-1 and interleukin-6.
Researchers have noted that disease activity seems to be increased in people who have RA and suffer from obesity. And the more overweight you are, the worse your symptoms tend to be.
But experts are not exactly sure how obesity affects RA, and it may come down to a chicken-and-egg question.
“I don’t think we really fully understand these connections,” says Dr. Michael George, a rheumatologist and instructor in the Division of Rheumatology in the Perelman School of Medicine at the University of Pennsylvania in Philadelphia. “Based on our work I’m not convinced that patients with obesity have more severe RA,” he adds.
“We know that obesity is associated with more pain, fatigue and osteoarthritis, and these could explain the more severe symptoms in patients with RA and obesity. In other words, symptoms related to obesity make us think the RA is worse, but actually, some of these symptoms may not be from the RA,” he explains.
“Increased disease activity has been measured in obese patients with RA,” George says. But he points out that this may not be a reliable indication of obesity’s effect on RA.
“The trouble is that most of these disease measures are based in large part on patient symptoms, so pain of any cause can increase disease activity measures,” he says.
“We have shown that obesity is also associated with increases in disease measures that are considered more objective, such as C-reactive protein, a blood marker used to measure inflammation, so the issue might be more how we measure disease activity.”
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In an odd twist, obesity may provide some protection against the joint damage that RA can cause.
“Multiple studies have shown that joint damage over time is less in obese patients with RA,” George points out.
“I agree that [studies] demonstrating that obese patients have fewer erosions of their affected joints is an important observation,” echoes Dr. Joan Von Feldt, who is a professor of medicine in the Division of Rheumatology at the University of Pennsylvania.
“Further study will be very important in determining obesity’s effect on RA,” adds Von Feldt, who is also the editor in chief of the Journal of Clinical Rheumatology.
There is also some evidence suggesting that being obese can potentially raise the risk of getting RA.
“Several studies have suggested that obesity might be a risk factor for the development of RA, although I think that this remains an unanswered question,” George says.
To further complicate matters, a study by Swedish researchers indicates that obesity may provide some protection against acquiring RA in men, but not women.
“There are likely important differences in how body composition changes in men and women with RA,” George explains. “In one of our studies, underweight men had the highest levels of inflammation, but we didn’t see this is women. Perhaps inflammation affects body composition differently in men and women,” he says, noting that being underweight may itself be a marker of severe disease.
“Patients with severe RA can experience weight loss and, in fact, [being] underweight [and having RA] is associated” with a higher risk of earlier death.
“It may be that other factors associated with obesity contribute to predisposition [to] RA,” Von Feldt says.
Obesity may also affect RA in other ways. According to arthritis.org, being obese may decrease the efficacy of many of the drugs used to treat RA. A 2013 study, published in the journal Arthritis Care & Research , reported that overweight and obese patients are as much as 50 percent less likely to have a positive outcome after 12 months of therapy with biologics that block TNF-alpha than healthy-weight patients. This poor response appears to be especially true with infliximab (Remicade).
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And much like everything else surrounding the question of obesity and RA, the reasons why drugs may be less effective in overweight people with RA are not understood.
“The metabolism of the medications is likely to be the same,” Von Feldt says. “However, patients may need higher doses than normal-weight patients.” She also points out that this is not true for all medications. “Each medication has different distribution to fat cells,” she says.
“The answers are not straightforward, but [how obesity affects RA] certainly is an important area of investigation,” George says.
Although future study is clearly required to sort out these issues, George points out that if you have RA and are overweight or obese, it’s important to try to lose weight.
“If patients with obesity have more severe symptoms, this is quite important,” George says. “Exercise and weight loss might be an important way to help patients with RA who are obese feel better and improve their overall health as well.”
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Does Being Obese Make Your Rheumatoid Arthritis Worse? originally appeared on usnews.com
