Antidepressant medications and change in mammographic density in postmenopausal women.

BACKGROUND Several studies suggest antidepressant medications can increase prolactin levels. Some, but not all, studies suggest prolactin levels are positively associated with mammographic breast density, an established risk factor for breast cancer. METHODS We evaluated 29,284 women with two routine screening mammograms 9 to 28 months apart between 1996 to 2006 to examine whether antidepressant use was associated with changes in mammographic breast density. Mammographic breast density was assigned by radiologists and coded according the Breast Imaging Reporting and Data System classification. Exposure to antidepressants was ascertained based on electronic pharmacy dispensing data, including dispensings from claims data. We used polytomous logistic regression to estimate the odds of an increase or decrease in density categories between mammograms associated with antidepressant initiation, continuation, and discontinuation compared with nonusers of any antidepressants. RESULTS Initiation, continuation, and discontinuation of antidepressant medications were not associated with changes in mammographic density. CONCLUSIONS The lack of association between antidepressant use and breast density is consistent with recent studies that do not suggest an association between antidepressant use and breast cancer risk.