Migraine Might Lower Breast Cancer Risk

THURSDAY, Nov. 6 (HealthDay News) -- Women who experience migraines may actually have a 30 percent lower risk of developing breast cancer, say researchers from the Fred Hutchinson Cancer Research Center in Seattle.

Levels of estrogen may be the key to this association: High levels of estrogen are associated with an increased risk of breast cancer, but women who suffer migraines appear to have low levels of the hormone, which may account for the reduction in breast cancer risk, the researchers explained.

"Women who suffer migraines suffer them either when they have fluctuations in their hormone levels or particularly low levels of hormones," said lead research epidemiologist Dr. Christopher I. Li.

Li noted that during pregnancy, when estrogen levels are high, migraines often stop. "Among migraine sufferers who reach the third trimester, 80 percent of them will not suffer any migraines," he said.

The report was published in the November issue ofCancer Epidemiology, Biomarkers & Prevention.

Not everyone is convinced that Li's theory is correct.

Dr. Ellen Drexler, associate director of the Division of Neurology at Maimonides Medical Center in Brooklyn, N.Y., doesn't think that estrogen levels explain the association between breast cancer risk and migraine.

"Migraine brains are more sensitive to many exogenous and endogenous factors, of which falling estrogen levels are an important one for many female migraineurs," Drexler said. "However, female migraineurs are not known to have consistently lower levels of estrogen than are non-migraineurs."

It is not clear that the lower incidence of breast cancer in women with migraines proves that the reason is lower estrogen levels, Drexler said.

"Genetic factors may also be playing a role, as well as exogenous factors such as medication use, smoking and alcohol use, which may vary between migraineurs and non-migraineurs," Drexler said. "In summary, an interesting study, but more work needs to be done to conclude that it has furthered our understanding of the biology of migraine or of breast cancer."

For the study, Li's team collected data on 3,412 postmenopausal women. Among these women, 1,938 had been diagnosed with breast cancer, and 1,474 had no history of the disease. The researcher also gathered information about migraines from the women.

The researchers found that women who suffered from migraines had a 30 percent lower risk of developing breast cancer compared with women with no history of migraine.