A recent study published in BMC Cancer has shed light on the potential link between migraine susceptibility and the risk of breast cancer. The research utilized Mendelian randomization (MR) analysis, a method that leverages genetic variations to infer causality between risk factors and health outcomes. Migraine, a common neurological disorder, predominantly affects women aged 25 to 55.
This condition has been associated with various health complications, including dementia, cardiovascular diseases, and possibly cancer. While some studies, like the Nurses’ Health Study, found no connection between migraines and breast cancer, others have indicated a potential link. Given the inconsistencies and limitations of traditional observational methods, there’s a pressing need for more definitive research on this topic. The researchers conducted a two-sample MR study to explore the causal relationship between migraines and breast cancer.
This method hinges on three core assumptions: genetic variations are strongly linked to the exposure (migraine), they are not related to potential confounders, and they don’t directly influence the outcome (breast cancer). The study sourced extensive GWAS data from individuals of European descent. Data related to any migraine (AM) was extracted from a recent study, which included over 100,000 cases and 770,000 controls.
From this data, subsets of migraine with aura (MA) and without aura (MO) were further analyzed. The GWAS statistics for breast cancer were sourced from the Breast Cancer Association Consortium, which had a vast sample size. The researchers meticulously selected instrumental variables, mainly single nucleotide polymorphisms (SNPs), ensuring they were strongly associated with migraines and not directly related to breast cancer outcomes.
Potential confounders like BMI and age of menopause were also accounted for. The study provided detailed insights into select SNPs, with observed F statistics ranging from 29.9 to 314.8. While associations related to AM and MO were strongly evidenced, the relationship between MA and breast cancer was less definitive due to its low explained variance.
After adjusting for potential confounders, an increase in genetically predicted AM was linked to a heightened risk of overall breast cancer, especially estrogen receptor-positive (ER+) breast cancer. However, AM did not show a significant effect on estrogen receptor-negative (ER-) breast cancer. Interestingly, migraines without aura (MO) were associated with a higher risk of overall breast cancer and a significant risk for ER- breast cancer.
However, the link between MO and ER+ breast cancer remained inconclusive. The study offers a fresh perspective on the potential relationship between migraines and breast cancer risk. While the findings suggest a connection, especially for those with migraines without aura, further research is essential to confirm these results and understand the underlying mechanisms.