Medication use and the risk of breast cancer.

PURPOSE: To investigate whether the use of commonly-prescribed medications, primarily antihypertensives and antidepressants, is associated with an increased risk of breast cancer.
METHODS: Participants from a population-based case-control study were re-contacted 5-8 years after the original study regarding prescription and non-prescription medication use during the 10 years prior to diagnosis. Controls (n = 647) were frequency-matched to the cases (n = 600) by 5-year age groups. Medication use information was obtained during a telephone interview, and participants were sent the questionnaire in advance to facilitate recall. Odds ratios and 95% confidence intervals were estimated using conditional logistic regression.
RESULTS: A slightly increased risk of breast cancer was associated with use of calcium channel blockers (CCBs), but there was no trend with increasing duration or recency of use. Breast cancer risk was not associated with use of antidepressants, beta blockers, corticosteroids, or non-steroidal anti-inflammatory drugs. Results were similar when analyses were restricted to cases with localized disease.
CONCLUSIONS: These results support previous findings that CCBs may be associated with modest increases in breast cancer risk, but not findings that non-steroidal anti-inflammatory use reduces risk.