Prolonged OC use linked to decline in risk of CVD: new analyses of WHI data also show decreased risk of endometrial, ovarian ca.(News)

PHILADELPHIA -- Extended use of oral contraceptives significantly reduces the risk of gynecologic cancers, as well as cardiovascular disease, according to two new analyses of data from the Women's Health Initiative.

The findings of a reduction in ovarian and endometrial cancer confirm previous reports, but the evidence of cardiovascular disease (CVD) risk reduction with oral contraceptive (OC) use contrasts with results of an earlier WHI analysis showing increased CVD risk with hormone therapy, said Rahi Victory, M.D., who was the lead investigator in both new analyses.

He presented the studies at the annual meeting of the American Society for Reproductive Medicine.

The difference in CVD risk between hormone therapy and OCs may be attributable to the availability of OCs in a wider variety of formulations and to the fact that OCs are given at a different dosage during a different period in a woman's life--when she is younger and healthier, suggested Michael Diamond, M.D., professor of obstetrics and gynecology at Wayne State University, Detroit, and a coauthor of the two studies.

"In the case of CVD, it may depend on the status of the cardiovascular system at the time the estrogen is taken. In individuals who are younger, who don't have a lot of atherosclerotic plaque, the estrogen may have beneficial effects in increasing nitric oxide production by the endothelial cells. In contrast, in someone who is older and who already has more atherosclerosis, estrogen may impact the cells in a detrimental way," he told this newspaper.

Each of the two analyses included almost 162,000 women from the WHI data-base. About 67,000 had a history of OC use.

After controlling for possible confounding factors, the investigators found that OC use was associated with small but significant reductions in multiple CVD outcomes. These included: