In 1995, the Mayo Clinic released a study on the incidence rate of alopecia areata in Olmsted County, Minnesota consisting of 292 participants who were newly diagnosed with alopecia areata from 1975 to 1989. This study set the only known lifetime risk for alopecia areata at 1.7%. (Lifetime risk means the risk of developing a disease during ones lifetime.) A newer study, with 530 qualifying participants, was recently released accessing the same data parameters but from 1990 to 2009 to document the most current lifetime incidence risk. They found that the risk of a person developing alopecia areata during their lifetime has increased to 2.1%.
Nearly 6.7m people in the U.S. (over 149m worldwide) will develop alopecia areata in their lifetime.
At 2.1%, the cumulative lifetime incidence of AA from this recent 20-year period was slightly higher than 1.7% observed in the older study. Similarly, REP data analyzed in studies of other autoimmune-associated diseases have shown that incidence of rheumatoid arthritis and systemic lupus erythematosis have also increased in the region in recent years. These data do not refute the hypothesis that autoimmune disease incidence maybe rising, generally.