Researchers from the Fred Hutchinson Cancer Research Center in Seattle said women who suffer migraine headaches may have as much as a 30 % lower risk of developing breast cancer. The study published in the November issue of Cancer Epidemiology, Biomarkers & Prevention, said the reason for this reduced risk could be the lower estrogen levels which migraine sufferers have.

Dr. Christopher I. Li lead research epidemiologist of the Fred Hutchinson Cancer Research Center in Seattle said, "Women who suffer migraines suffer them either when they have fluctuations in their hormone levels or particularly low levels of hormones.”

“Many of the triggers of migraine in women are known to be hormonally related, and also are important in the development of breast cancer. We now see a plausible relationship between hormones and migraines and breast cancer," said Li.

In the study researchers studied the data from two studies of 3412 postmenopausal women in the age bracket of 55 to 79 years. Of these 1938 had been diagnosed with invasive breast cancer while 1474 women were without the disease.

"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."

One of the reasons could be the medications women take for their migraine headaches. "These women may be more frequent users of NSAIDs [nonsteroidal anti-inflammatory drugs]," he says "There is evidence that use of NSAIDs is protective against breast cancer, so part of this reduction could be related to use of that medication, though it is unlikely to account for the whole reduction."

Len Lichtenfeld, MD, deputy chief medical officer of the American Cancer Society said, "This potentially points to new mechanisms that may be related to breast cancer prevention. If we can uncover what those are, it may lead to new ways to treat breast cancer. You can't absolutely say for sure that what the researchers are measuring is in fact responsible for higher or lower risk of breast cancer,"

Migraine expert Dr. Stephen Silberstein, director of the Jefferson Headache Center at Thomas Jefferson University Hospital in Philadelphia, said "This study doesn't prove anything," Silberstein said. "It's not that I don't believe the results, it's that the results are not believable."

Li said the possibility of a connection between migraines and breast cancer, should be interpreted with caution, but in an optimistic light. "Advancing our understanding of the mechanisms of migraine may improve our understanding of how we could potentially reduce breast cancer risk," he said.