Inflammatory Autoimmune Diseases Becoming Commonplace?
Inflammatory autoimmune diseases, such as rheumatoid arthritis (RA), are relatively common conditions, especially among adults aged 50 and older.
Researchers say the risk of developing an autoimmune disease depends on a number of factors, including age and gender, but until now there hasn't been an easy-to-understand average risk over a person's lifetime for adults in the U.S.
"We estimated the lifetime risk for rheumatic disease for both sexes, something that had not been done before," researcher Cynthia Crowson, a biostastician at the Mayo Clinic, says in a news release. "Prevalence and incidence rates existed, but prevalence figures underestimate individual risk and incidence rates express only a yearly estimate."
Researchers say the risk of autoimmune diseases changes at every age, but the results can serve as a guide in counseling people regarding their overall risk of autoimmune disease conditions.
New Rheumatoid Arthritis (RA) Risk Estimates
The study, determined the average risk of developing one of seven of the most common autoimmune disorders over a person's lifetime, including: rheumatoid arthritis (RA), polymyalgia rheumatica, systemic lupus erythematosus, giant cell arteritis, a, psoriatic arthritis, Sjögren's syndrome and anklosing spondylitis
Researchers based their estimates on the number of autoimmune diseases diagnosed between 1955 and 2007 among 1,179 residents of Olmstead County, Minn., and then extrapolated their results to the general population.
The results suggest that one in 28 women (3.6%) and one in 59 (1.7%) of men will develop rheumatoid arthritis, the most common autoimmune disease, in their lifetime. The second most common autoimmune disorder according to the study was polymyalgia rheumatica (PMR), an inflammatory disorder involving pain and stiffness in the hip or shoulder area, with a lifetime risk of 2.4% for women and 1.7% for men.
Overall, researchers estimate 8.4% of women (1 in 12) and 5.1% (1 in 20) of men will develop some type of autoimmune disease in their lifetime.
Crowson, C. Arthritis and Rheumatism, Jan. 5, 2011, online edition.
News release, Mayo Clinic.