Associations between oral contraceptive (OC) use and breast cancer have been reported, but few studies have considered associations in racial and ethnic minorities. Data regarding injected or implanted hormonal contraceptives are limited. In a case-control study of Hispanic (796 cases, 919 controls) and non-Hispanic white (1,522 cases, 1,596 controls) women in the U.S. southwest interviewed in 2000-2005, 49% of Hispanic controls and 66% of non-Hispanic white controls reported having used OC. Breast cancer odds ratios (OR) associated with OC use within the past 5 years were 1.22 (95% confidence interval (CI) 0.80, 1.84) among Hispanics, 1.28 (95% CI 0.93, 1.76) among non-Hispanic whites, 1.27 (95% CI 0.99, 1.63) for both ethnic groups combined and 1.53 (95% CI 0.98, 2.40) for estrogen receptor (ER) negative tumors. OC use for 20 years or longer was associated with ORs of 1.50 (95% CI 1.04, 2.17) for both ethnic groups combined, and 2.23 (95% CI 1.17, 4.25) for ER negative tumors. Hormonal contraceptive injections were used by 3.3% of Hispanic controls and 2.8% of non-Hispanic white controls, OR 1.23 (95% CI 0.88, 1.73). Fifteen cases and 2 controls reported use of a subdermal contraceptive implant, OR 8.59 (95% CI 1.92, 38.39). Associations between OC use and breast cancer in Hispanics are consistent with modestly increased risk among recent users and for ER negative tumors, as observed in other populations. Based on a small number of users of contraceptive implants, a significantly increased breast cancer risk was observed; continued surveillance of implant users may be warranted.
(c) 2007 Wiley-Liss, Inc.