According to a recent study women who suffer from migraines have some reason to cheer-a reduced risk of breast cancer compared to women who did not suffer from migraine headaches.

The study, which appears in the July issue of Cancer Epidemiology, Biomarkers & Prevention, said the risk may be reduced by as much as 26%, irrespective of the woman’s age or what the migraine triggers were.

The study is a follow-up to research published in 2008 and found a similar significantly reduced breast cancer risk for migraine sufferers.

Christopher Li, MD, PhD, a breast cancer epidemiologist and associate member of the Fred Hutchinson Cancer Research Center's Public Health Sciences Division in Seattle and the lead author of both studies said, "In this study, we evaluated the relationship between migraine and breast cancer risk and found that women who have migraine have a 26 percent lower risk of breast cancer than women without a history of migraine."

However Li said researchers weren’t sure exactly why women who get migraines appear to have a reduced breast cancer risk, but they suspect that hormones, particularly estrogen, to be the reason.

"It's pretty clear that migraine, like breast cancer, is a hormonally related disease. Many triggers for migraine are also things that reduce estrogen levels," he said.

In the first study of postmenopausal women Li and his colleagues evaluated 1,938 women with breast cancer and 1,474 healthy women, ages 55 to 79, and found up to a 33% reduction in the risk of breast cancer among women with migraine.

In the current study Li and colleagues studied data from 4,568 women with breast cancer and 4,678 women without breast cancer between the ages of 34 to 64.

All the women answered the same questions about migraine history, reproductive history, use of hormone therapy or birth control pills, menopausal status, body mass index, alcohol use, and smoking status.

The researchers found that women who had a history of migraine had a 26 % reduced risk of developing breast cancer.

Li said, "It does appear that migraines may protect women from breast cancer, and that it's equally protective for both younger and older women. We see a 26% reduction in risk associated with migraine."

The new research rules out many of the other explanations for why women with migraines may have a lower risk of breast cancer, such as migraine sufferers being less likely to drink or use hormones. "Migraine may in fact be an independent predictor of breast cancer reduction risk," Li said.  

"This research suggests that women with migraine may have a lower risk of breast cancer," said Li, who added that women with migraines should "still have the same breast cancer screenings and follow-up."

Len Lichtenfeld, MD, deputy chief medical officer of the American Cancer Society in Atlanta said, "The real connection is unclear. Could it be hormones? Yes," he said, but added that it could be other factors as well.

Scott Maul, MD, a medical oncologist in Milwaukee who also reviewed the study for WebMD said the potential link between migraines and reduced breast cancer risk does make sense. Higher lifetime exposure to estrogen is a known risk factor for breast cancer, and some migraines seem to be associated with a drop in estrogen. "But not all migraines are due to hormone fluctuations," he said. "It's hardly a conclusive study," he concluded.