Rheumatoid Arthritis Incidence on the Rise in Women

http://www.sciencedaily.com/releases/2010/05/100526111324.htm

ScienceDaily (May 27, 2010) — The incidence of rheumatoid arthritis (RA) in women has risen during the period of 1995 to 2007, according to a newly published study by researchers from the Mayo Clinic. This rise in RA follows a 4-decade period of decline and study authors speculate environmental factors such as cigarette smoking, vitamin D deficiency, and lower dose synthetic estrogens in oral contraceptives may be the source of the increase.

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Prior studies have clearly demonstrated that cigarette smoking is associated with a greater risk for RA development in both sexes. While smoking rates in the U.S. are declining, the rate is significantly slower in women than men, which researchers believe may, in part, explain the modest increase of RA incidence in women. Researchers also note that lower doses of estrogens found in modern oral contraceptives offer less protection against RA development then at the previously higher doses found in older medications, which they suspect may contribute to the increased RA incidence among women. Furthermore, several studies have shown vitamin D deficiency to be associated with RA development and coupled with evidence that this deficiency, particularly in women, has risen over the past decades the Mayo team considered it a possible contributor to the upward trend in RA.
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