10 Things You Don’t Know About Rheumatoid Arthritis
If you or someone you love has rheumatoid arthritis (RA) there’s probably a lot you already know about the disease, like the fact that it’s a chronic illness that causes joint inflammation and pain, or that it affects three to four times as many women as men. But RA is still pretty mysterious—the exact cause is unknown, for instance, as is why it strikes more women (though theories point to hormonal and immune system differences)—and so researchers are busy sharing new insights on the regular. Here are 10 surprising facts and promising theories you should know about RA.
RA Is Not a Joint Disease
“This is probably the biggest difference in how rheumatologists view RA and how others see it,” says Howard Feinberg, D.O., a professor of rheumatology at Touro University California College of Osteopathic Medicine in Vallejo, CA. “Most people think of RA as an arthritis disease that also does all these other things like cause heart or lung problems.” But in fact, he says, RA causes the immune system to attack almost every part of the body—the heart, lungs, eyes, skin, liver, kidneys, etc.—and it manifests in different ways for different people. “It’s possible that our genetics are what cause the disease to show up differently, but that’s still a theory we’re looking at,” says. Dr. Feinberg.
RA Blood Tests Aren’t Super Reliable
One sign of RA is higher levels of certain antibodies—rheumatoid factor (RF) and anti-cyclic citrullinated peptides (anti-CCP)—which indicate the immune system is working in overdrive. But the blood tests for RF and anti-CCP simply aren’t that sensitive, so they don’t detect the antibodies when levels are low. “Anti-CCP has a sensitivity of only 60%, which means that 40% of patients with RA will have a negative test,” says Dr. Feinberg. Rheumatoid factor is even less accurate—it’s positive in only 40% of patients with early disease. “Patients with negative tests, called seronegative RA, still have RA and require the same treatment as patients with a positive test (seropositive RA). Seronegative RA is a little less aggressive, but it can still cause all of the same problems,” says Dr. Feinberg.
RA Is Linked to Gum Disease
When experts noticed that rheumatoid arthritis and gum disease seem to go hand in hand, suspicions about oral bacteria arose. The link was recently confirmed by Johns Hopkins University researchers, who found one oral bacteria in particular—Aggregatibacter actinomycetemcomitans—triggered an overproduction of antibodies that create inflammation and attack joints in RA patients. But as Dr. Feinberg explains, this itself can lead to gum disease, so it’s also possible that RA is causing the gum disease. “We know there’s a link between gum disease and overall health, but we're still in our infancy of understanding human bacteria and its relationship to diseases.”
High Rates of Urinary Tract Infections Are Related, Too
If you recall having had more than your fair share of UTIs in the years leading up to your RA diagnosis, there’s a good chance it wasn’t a coincidence. A recent study in Rheumatic & Musculoskeletal Diseases found that RA patients experienced significantly more urinary tract, genital, and general viral and bacterial infections in the six years prior to their diagnosis. Though more research is needed, researchers suggest that frequent infections could serve as a signal to watch for RA development.
Pregnancy RA Remission Led to a Breakthrough
No doubt you’ve heard that many women’s RA symptoms improve during pregnancy. (In fact, up to 40% of pregnant women may achieve remission, according to a research review in Open Access Rheumatology.) But did you know that this trend led researchers to a new treatment for RA? “Steroids were actually discovered when a rheumatologist at Mayo Clinic saw that pregnant women with RA got better and figured it must be something they produced, and he found it was cortisol,” says David Pisetsky, M.D., professor of medicine and immunology at Duke University Medical Center. Indeed, women’s levels of cortisol, a steroid hormone, increase significantly during pregnancy. “Ultimately, that’s how prednisone became a treatment for RA.”
Giving Birth Can Trigger RA Onset
Pregnancy might have some protective powers for women with existing RA, but having a baby can unfortunately also set off the disease in others. “The research has shown a 20-fold increase in the risk of developing rheumatoid arthritis within the first year of pregnancy,” says Dr. Feinberg. Female hormonal factors are a primary suspect, but the science is far from conclusive. “The theory is that these women were prone to rheumatoid arthritis and probably would have developed it anyway, but the effects of pregnancy triggered it sooner,” says Dr. Feinberg.
Some Vaccines Are a Concern
Rheumatoid arthritis treatments that are designed to suppress the immune system can leave patients more vulnerable to infection—including those from weakened disease-causing strains used in live-attenuated vaccines. In other words, a live vaccine can cause the very infection it’s intended to prevent in RA patients. “Fortunately, the number of live vaccines that adults need to take is fairly limited,” says Anca Askanase, M.D., director of rheumatology clinical trials at Columbia University Irving Medical Center in New York City. For instance, the intranasal influenza vaccine is a live vaccine, but the regular flu shot is not. “Other live vaccines include measles, mumps, rubella, and yellow fever. If you really need those, work with your doctor to get off the immunosuppressants long enough to allow for a good response.”
Most People With RA Have No Family History of the Disease
That’s not to say genetics aren’t a factor—they certainly play a role. “We know there is a specific gene, HLA-DRB1, that increases the likelihood of developing rheumatoid arthritis, but this isn’t a disease where if you have the gene, you’re automatically going to get it,” says Dr. Feinberg. In fact, a research review in Clinical Reviews in Allergy & Immunology estimated the contribution of the gene to heritability to be only about 11% to 37%. Also key are environmental triggers, or something that turns that gene on and gets it started. “We know for sure that one of those triggers is cigarette smoking; a lot of researchers are also looking at very specific chemicals, pollutants, viruses, and other environmental factors,” says Dr. Feinberg.
RA Doubles Your Risk of Dying of Heart Disease
When you consider that RA causes inflammation in all the tissues of the body, it makes sense that the cardiovascular system is affected—but the extent is still shocking. “Rheumatoid arthritis increases your risk of heart disease even more than diabetes does,” says Dr. Feinberg. This is true even in people with no pre-existing risk factors, because RA itself is a risk factor. “The inflammation associated with RA can cause atherosclerosis or hardening of the arteries, and it lowers levels of HDL or good cholesterol,” Dr. Feinberg explains. Fortunately, treating RA can lower the risk of heart disease, heart attacks, and stroke, once again stressing the importance of staying on top of managing the disease.
- Women’s Hormones and RA: Rheumatology. (2017). "The Role of Female Hormonal Factors in the Development of Rheumatoid Arthritis." academic.oup.com/rheumatology/article/56/8/1254/2631597
- Gum Disease and RA: Science Translational Medicine. (2016). "Aggregatibacter actinomycetemcomitans-induced hypercitrullination links periodontal infection to autoimmunity in rheumatoid arthritis." pubmed.ncbi.nlm.nih.gov/27974664/
- Urinary Tract Infections and RA: Rheumatoid & Musculoskeletal Diseases. (2020). "Increased primary care use for musculoskeletal symptoms, infections and comorbidities in the years before the diagnosis of inflammatory arthritis." rmdopen.bmj.com/content/6/2/e001163
- Urinary Tract Infections and Long-Term Steroid Use: Clinical Rheumatology. (2013). "Urinary tract infections in patients with rheumatoid arthritis." pubmed.ncbi.nlm.nih.gov/23238605/
- Cortisone Discovered: Mayo Clinic Proceedings. (2010). "Rheumatology Practice at Mayo Clinic: The First 40 Years–1920 to 1960." ncbi.nlm.nih.gov/pmc/articles/PMC2848437/
- Pregnancy and RA Remission: Open Access Rheumatology. (2016). "Management of rheumatoid arthritis during pregnancy: challenges and solutions." ncbi.nlm.nih.gov/pmc/articles/PMC5098768/
- RA and Premature Birth: Annals of the Rheumatic Diseases. (2018). "Foetal-neonatal and maternal outcomes in women with rheumatoid arthritis." pubmed.ncbi.nlm.nih.gov/25393524/
- Giving Birth Triggers RA: Rheumatology. (2017). "The role of female hormonal factors in the development of rheumatoid arthritis." academic.oup.com/rheumatology/article/56/8/1254/2631597
- COVID-19 Vaccines Aren’t Live: Centers for Disease Control and Prevention. (2020). "Facts About COVID-19 Vaccines." cdc.gov/coronavirus/2019-ncov/vaccines/about-vaccines/vaccine-myths.html
- Heritability of RA: Clinical Reviews in Allergy & Immunology. (2013). "Genetics of Rheumatoid Arthritis — A Comprehensive Review." ncbi.nlm.nih.gov/pmc/articles/PMC3655138/
- RA and Heart Disease Risk: Arthritis & Rheumatism. (2008). "Risk of cardiovascular mortality in patients with rheumatoid arthritis: a meta-analysis of observational studies." pubmed.ncbi.nlm.nih.gov/19035419/