Oral contraceptive use and risk of breast cancer in middle-aged women.

The authors used data from a population-based, case-control study of breast cancer conducted among women residing in King County, Washington State, who were 50-64 years of age in 1988-1990, to examine the relation of oral contraceptive use to the risk of breast cancer. There were no clear differences between cases and controls with respect to the total duration of oral contraceptive use, time since last use, or age at first or last use. While a small increase in risk was noted in women who had first used oral contraceptives within 20 years of the interview reference date, within that period there was no trend in risk observed with decreasing amounts of time since the last use of these agents. Overall, this study supports the absence of any strong association between oral contraceptive use and breast cancer risk during middle age in the cohort of women who first used these drugs.