Aspirin Metabolites and Mammographic Breast Density in Premenopausal Women.

BACKGROUND: Studies investigating the associations of self-reported aspirin use and mammographic breast density (MBD) have reported conflicting results. We, therefore, investigated the associations of aspirin metabolites, with MBD in premenopausal women.

METHODS: We performed this study on 705 premenopausal women who had fasting blood draw for metabolomic profiling. We performed covariate-adjusted linear regression models to calculate the least squares means of volumetric measures of MBD (volumetric percent density (VPD), dense volume (DV), and non-dense volume (NDV)) by quartiles of aspirin metabolites (salicyluric glucuronide, 2-hydroxyhippurate (salicylurate), salicylate, and 2,6-dihydroxybenzoic acid).

RESULTS: Approximately 13% of participants reported taking aspirin in the past 12 months. Aspirin users had higher levels of 2-hydroxyhippurate (salicylurate), salicylate, and salicyluric glucuronide (peak area) than non-users, but only mean peak area of salicyluric glucuronide increased by both dose (1-2 tabs per day=1,140,663.7, and ≥3 tabs per day=1,380,476.0) and frequency (days per week: 1 day=888,129.3, 2-3 days=1,199,897.9 and ≥4 days=1,654,637.0). Aspirin metabolites were not monotonically associated with VPD, DV, or NDV.

CONCLUSIONS: Given the null results, additional research investigating the associations of aspirin metabolites in breast tissue and MBD is necessary.

IMPACT: Elucidating the determinants of MBD, a strong risk factor for breast cancer, can play an important role in breast cancer prevention. Future studies should determine the associations of non-aspirin non-steroidal anti-inflammatory drug metabolites with MBD.