KaiserNetwork.org Daily Reproductive Health Report
October 21, 2004
Women who use oral contraceptives have lower risks of heart disease, stroke, uterine and ovarian cancers and elevated cholesterol levels and no increased risk of breast cancer, according to the findings of a large federal study that were presented Wednesday in Philadelphia at the annual meeting of the American Society for Reproductive Medicine, the AP/Richmond Times-Dispatch reports. Dr. Rahi Victory of Wayne State University in Detroit and colleagues studied 162,000 women at 40 locations throughout the United States as part of the $625 million, NIH-funded Women's Health Initiative -- the largest women's health study ever conducted and one of the largest on oral contraceptives. Of the women studied, 67,000 had taken oral contraceptives at some point in their lives (Marchione, AP/Richmond Times-Dispatch, 10/21). Among women who had taken oral contraceptives, the risk of hypertension, heart attack, stroke, aneurysm and high cholesterol was reduced 8% to 10%, and the risk of needing surgical procedures -- such as angiograms and bypasses -- was reduced 20% to 50%, the Los Angeles Times reports (Maugh, Los Angeles Times, 10/21). Overall, women who had taken oral contraceptives also had a 7% lower risk of developing any type of cancer, an 18% lower risk of developing uterine cancer and a 19% lower risk of developing ovarian cancer than women who had never taken oral contraceptives.
Among women who had taken oral contraceptives for four or more years, the risk of certain cancers was further reduced, according to the study. Women who took the pill for four or more years had a 13% lower risk of developing any type of cancer, a 42% lower risk of developing ovarian cancer and a 30% lower risk of developing uterine cancer than women who never used oral contraceptives (AP/Richmond Times-Dispatch, 10/21). Researchers also found that taking oral contraceptives had no effect on the risk of developing other cancers, including breast, colon and bladder cancers. However, that finding was seen as positive because previous studies had linked oral contraceptive use to an increased risk of breast cancer, according to the Times. Although women who had a history of both oral contraceptive use and cigarette smoking did not experience the same degree of lowered risks for cancer and disease as nonsmokers, female smokers who took oral contraceptives were still at lower risk for cancer and disease than smokers who did not take oral contraceptives (Los Angeles Times, 10/21).
According to physicians, the type of hormones women use and the stage of life when they are used might explain why hormones are beneficial to some people and harmful to others, the AP/Times-Dispatch reports. Although most oral contraceptives are a combination of synthetic forms of estrogen and progestin in various doses, women who take similar hormones after menopause in the form of hormone replacement therapy are more likely to have heart disease and some cancers, according to previous findings of the WHI study, according to the AP/Times-Dispatch. "We're still learning more and more about the biology," WSU research Dr. Michael Diamond said. However, women who take oral contraceptives and later discontinue them likely still experience the benefits, according to Victory (AP/Richmond Times-Dispatch, 10/21). Diamond added that the new findings should be "very reassuring" for women who take oral contraceptives (Los Angeles Times, 10/21). No producers of oral contraceptives financed any part of the WHI study, according to the AP/Times-Dispatch (AP/Richmond Times-Dispatch, 10/21).