Reports: more women are getting rheumatoid arthritis
According to a recent study from the Mayo Clinic, rheumatoid arthritis ( RA) in women has increased between the years 1995 and 2007. This rise follows a four year decline in the disease and is speculated to be effected by environmental factors such as cigarette smoking, vitamin D deficiency and lower dose synthetic estrogens in oral contraceptives.
The Mayo Clinic study was published in June in the journal Arthritis and Rheumatism and included over 50 years of epidemiological data. RA is a chronic inflammatory disease that attacks skeletal joints, effecting between 1 million and 2 million Americans. People with RA usually become unable to work within 10 to 20 years and have a 60 percent to 70 percent higher mortality risk than the general population. Treatment of RA accounts for $ 9 billion in excess health care costs with direct and indirect costs expected to exceed $ 39 billion annually.
The research team was lead by Sherine Gabriel, M. D., M. Sc., and compared current findings to prior research conducted between 1955 and 1994 at the Mayo Clinic. Examining the medical records of 1,761 Olmsted County, Minnesota residents 18 years and older who had received one or more diagnoses of arthritis of varying types, they found that 466 had a diagnosis of RA. The mean age of diagnosis was 55.6 years and 69 percent of the RA patients were females.
Although a 2.5 percent increase in the incidence of RA in women was found, there was a 0.5 percent decrease noted in men. Prior studies have shown that cigarette smoking increases the risk of RA in both sexes. Cigarette smoking has been on the decline in the U. S., but the rate is slower in women than men, a factor that might help explain the gender differences in RA. Researchers also point out that modern oral contraceptives have lower doses of estrogens than older medications. The higher doses of estrogen in the prior contraceptives offer greater resistance to RA development. Finally, several studies have found that Vitamin D deficien- cies can contribute to developing RA and that this deficiency has increased in women over the past decades.
Dr. Ted Mikuls of the University of Nebraska Medical Center commented in the same issue of Arthritis and Rheumatism that, “ Public health measures are already under way to address many of the environmental risk factors that have been implicated in RA risk, including interventions that encourage smoking cessation and efforts focused at optimizing levels of physical activity, vitamin D intake, and oral hygiene.” He concluded, “ Reasons for the increase in incidence we found are unknown, but environmental factors likely play a role and should be further explored.”