Migraines may cut breast cancer risk by 30%

The study is the first to look at the relationship between breast cancer and migraines and its findings may point to new ways of reducing a woman's breast cancer risk, they said.

"We found that, overall, women who had a history of migraines had a 30 percent lower risk of breast cancer compared to women who did not have a history of such headaches," said Dr. Christopher Li of the Fred Hutchinson Cancer Research Center in Seattle, whose findings appear in the journal Cancer Epidemiology, Biomarkers and Prevention.

Li said the reduction in risk was for the most common types of breast cancers -- those driven by hormones, such as estrogen-receptor positive breast cancer, which is fueled by estrogen, and progesterone-receptor positive breast cancer, which is fueled by progesterone.

"Many of the triggers of migraine in women are known to be hormonally related, and also are important in the development of breast cancer," Christopher Li, MD, of the Fred Hutchinson Cancer Research Center in Seattle, tells WebMD. "We now see a plausible relationship between hormones and migraines and breast cancer."

The researchers combined data from two studies of 3,412 postmenopausal women (aged 55 to 79 years old) in the Seattle area, including 1,938 who'd been diagnosed with invasive breast cancer and 1,474 women without breast cancer. Information on migraine history was limited to cases diagnosed by health professionals.

"Women who reported a clinical diagnosis of migraine had a 33 percent reduced risk of IDC [invasive ductal carcinoma] and a 32 percent reduced risk of ILC [invasive lobular carcinoma] compared with women with no history of migraine," the authors write. "These reductions in risk did not vary substantially by age at migraine diagnosis or by history of ever using prescription migraine medications."

Breast cancer is the leading cause of cancer death among women worldwide, with an estimated 465,000 deaths annually, according to the American Cancer Society.