Jan. 11, 2011 -- One in 12 women and one in 20 men in the U.S. will develop some sort of autoimmune disease in their lifetime, according to new estimates.
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.
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 in the study was polymyalgia rheumatica (PMR) with a lifetime risk of 2.4% for women and 1.7% for men.
"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 these conditions.
New RA Risk Estimates
The study, published in Arthritis and Rheumatism, determined the average risk of developing one of seven of the most common autoimmune disorders over a person’s lifetime, including: rheumatoid arthritis, systemic lupus erythematosus, psoriatic arthritis, polymyalgia rheumatica, giant cell arteritis, ankylosing spondylitis, and Sjögren’s syndrome.
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.
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.
Specifically, the lifetime risk of the six autoimmune diseases examined in the study were:
3.6% or 1 in 28
1.7% or 1 in 59
|Systemic Lupus Erythematosus|
|Giant Cell Arteritis|
|Primary Sjögrens syndrome|
Researchers say these figures represent a substantial risk and could have implications on national disease awareness campaigns and research into diagnosis and treatments for autoimmune diseases.