Migraine and breast cancer risk: a meta-analysis of observational studies based on MOOSE compliant

It has long been speculated that migraine may contribute to an increased risk of breast cancer; however, results from previous studies have been inconclusive. To definitively interrogate this issue, we performed a meta-analysis to assess the correlation between these 2 diseases. Medline and PubMed were searched to identify relevant studies that had been published until October 2015. Based on a random effects model, relative risk (RR) and the corresponding 95% confidence interval (CI) were used to evaluate the pooled risk. A total of 7 studies involving 17,776 cases and 162,954 participants were included. Our study revealed that there was an inverse relationship between migraine and total breast cancer risk, with RR (95%CI) was 0.78 (0.66, 0.92). In subgroup-analysis, such an inverse relationship was also identified in the ductal and lobular carcinoma, case–control studies, and the ER(+)/PR(+) breast cancer. Little evidence indicative of a publication bias was uncovered. In conclusion, our study implicates a statistically significant inverse association between migraine and the risk of breast cancer. However, larger prospective cohort studies concerning other geographic populations to assess the association between migraine and the breast cancer risk are warranted.