If it feels like you’re hearing about autoimmune diseases like rheumatoid arthritis more and more these days, it’s not just coincidence. According to a new study published in Arthritis & Rheumatology, the number of people with autoimmune diseases—basically, when your immune system attacks your own body by mistake—is on the rise in the United States.
To figure this out, researchers looked at 14,211 study participants’ blood for things called antinuclear antibodies (ANA). ANA is the most common marker of autoimmunity. Researchers looked at blood samples from three separate time periods (1988-1991, 1994-2004, and 2011-2012) to see how prevalence of autoimmunity has changed in the U.S. population.
From 1988-1991 to 2011-2012, prevalence of ANA jumped from 11.0% to 15.9%--or 22 million to 41 million people with autoimmunity.
But why might autoimmune disorders be increasing?
"The reasons for the increasing prevalence of ANA, which were most pronounced in adolescents, males, and non-Hispanic whites, remain unclear," said study author Frederick W. Miller, M.D. of the National Institute of Environmental Health Sciences. "They are concerning, however, as they may herald an increase in autoimmune disorders, and emphasize the need for additional studies to determine the driving forces underlying these findings and to enable the development of possible preventative measures."
A positive ANA does not equal having an autoimmune disease, though a positive ANA can be a precursor to a diagnosed autoimmune disorder.
Autoimmune Diseases: The Basics
There are more than 80 known types of autoimmune diseases, the National Institutes of Health (NIH) says—and they’re complicated, to say the least. In fact, scientists are still trying to figure out what exactly causes them to develop in the first place. So far, experts believe that a combination of genetics and environmental factors are involved, per the NIH.
So that means if you have other members of your family who have autoimmune diseases, your risk is increased as well, says the NIH. Women also appear to be at higher risk than men for autoimmune disease—especially African-American, Hispanic-American, and Native-American women.
Typically, the immune system works to fight off invaders in the body, like infection with viruses or bacteria, according to the NIH. But in people with autoimmune diseases, the immune system malfunctions and attacks the body even when it’s not supposed to. Autoimmunity can affect many different parts of the body, and often results in symptoms like fatigue, low fever, swelling, redness, and pain, the NIH says—many of these symptoms are the result of inflammation triggered by the immune system. Some autoimmune diseases, like rheumatoid arthritis, can affect your joints, causing pain and stiffness. Others, like psoriasis, cause skin changes like itchy or sore patches.
Thankfully, there are treatments available for autoimmune problems. They vary based on the specific disease, but often include things like steroids or other things to manage inflammation, the NIH says.