CHICAGO – Over a three-year period, the risk of developingmultiple sclerosis (MS) was reduced in women taking oralcontraceptives, according to a study in the September issue of Archivesof Neurology, one of the JAMA/Archives journals.
In previousstudies, estrogen delayed the onset and eased the course of a MS-likedisease in animals, suggesting that oral contraceptives, which containestrogen, and pregnancy and the postpartum period afterward, bothstates associated with profound hormonal changes, may alter theclinical course or affect the risk of developing the disease, accordingto background information in the article.
Álvaro Alonso, M.D.,Ph.D., of the Harvard School of Public Health, Boston, and colleaguescompared 106 women who had a new diagnosis of MS between January 1,1993 and December 31, 2000 with 1,001 matched women without MS ascontrols. Individuals included in the analysis were drawn from aresearch database that includes medical and pharmacy records for threemillion Britons.
"The incidence of MS in OC [oral contraceptives]users was 40 percent lower than in nonusers," the authors report."Women had a higher risk of developing first symptoms of MS in the sixmonths following a pregnancy and a non-significant lower risk duringpregnancy, compared with those with no pregnancy. … This is consistentwith studies on the effect of pregnancy in patients with MS and theimmunological changes associated with pregnancy."
"Recent OC useand, possibly, current pregnancy are associated with a lower risk ofdeveloping MS," the authors conclude. "On the contrary, the postpartumperiod confers a higher risk of MS onset. Our findings suggest thathigh levels of exogenous [from outside the body] estrogens from OC useand of endogenous [from the body] estrogens during pregnancy may delaythe first clinical attack of MS."
(Arch Neurol. 2005; 62:1362-1365. Available pre-embargo to the media at www.jamamedia.org.)
Editor'sNote: This study was supported by a grant from the National MultipleSclerosis Society, New York, N.Y. Dr. Alonso was supported by aFulbright Program fellowship, New York.
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