Migraine and subsequent risk of breast cancer: a prospective cohort study.
Academic Article
Overview
abstract
PURPOSE: Previous studies have suggested that migraineurs are at decreased risk for developing breast cancer. Further prospective studies are warranted to confirm these results. In addition, studies evaluating migraine characteristics (e.g., migraine subtypes and frequency) are lacking. METHODS: We conducted a prospective cohort study among 39,696 participants in the Women's Health Study who were 45 years and older at study entry. Information on migraine was self-reported with good validation rates. Incident breast cancer cases were confirmed by medical record review. We distinguished the following major endpoints: any breast cancer, a combined endpoint of invasive and in situ cases, in situ breast cancer only, and invasive breast cancer only. Cox proportional hazards models were used to calculate age- and multivariable-adjusted hazard ratios (HRs) and 95 % confidence intervals (95 % CI). RESULTS: A total of 7,318 (18.4 %) women reported any migraine. During a mean follow-up time of 13.6 years, 432 in situ and 1,846 invasive breast cancer cases occurred. Migraine was not associated with breast cancer risk. The multivariable-adjusted HRs (95 % CI) were 1.10 (0.99-1.22) for any breast cancer, 1.06 (0.83-1.35) for in situ breast cancer, and 1.11 (0.99-1.25) for invasive breast cancer. The risk for developing breast cancer differed according to hormone receptor status with a suggestion of increased risks for hormone receptor negative tumors (HR ER-/PR- : 1.28, 95 % CI: 0.96-1.71). We did not observe meaningful differences with regard to histologic subtype or according to migraine aura status or migraine attack frequency. CONCLUSIONS: Results of our study do not support the hypothesis that migraineurs have a decreased risk for breast cancer.
