Oral Contraceptives and Breast Cancer Risk Among Younger Women

Background: Several studies have suggested a link between oral contraceptive use and breast cancer in younger women, but it is possible that chance or bias, including selective screening of contraceptive users, contributed to the putative association. Purpose: Given that oral contraceptives were first marketed in the United States in the early 1960s, we conducted a population-based case-control study to examine the relationship between use of oral contraceptives and breast cancer among women in a recently assembled cohort, focusing on women younger than 45 years of age who had the opportunity for exposure throughout their entire reproductive years. Methods: Breast cancer patients and healthy control subjects were identified, the latter group by random-digit dialing, in Atlanta, Ga., Seattle/Puget Sound, Wash., and central New Jersey.