Lower risk of breast cancer linked -- once again -- to migraines

Researchers at the Fred Hutchinson Cancer Research Center conducted a follow-up study to their original research - a first-of-its-kind study that linked migraines with breast cancer risk reduction. The results of the second study confirmed their original findings, showing that there was a 26 percent reduced risk of breast cancer in women who had been clinically diagnosed with migraines. And regardless of a woman's menopausal status, the age she was diagnosed with migraines, the use of prescription migraine medication and whether she avoided such migraine triggers as alcohol consumption, they found that the risk reduction "remained statistically" similar.

The second study was broadened considerably. According to Christopher I. Li, M.D., Ph.D., a breast cancer epidemiologist and associate member of the Hutchinson Center's Public Health Sciences Division, it involved four times as many participants - more than 4,500 cases and controls compared to approximately 1,000 each in the first study. "From an epidemiological perspective, having a larger and more diverse study in its underlying population helps in replicating the finding," he notes.

In addition, the age range was extended to between 34 and 64, compared to between 55 and 74 for the original study. "We were able to look at whether this association was seen among both pre-menopausal and post menopausal women," Dr. Li says. "In breast cancer this is relevant because there are certain risk factors that are different between older and younger women. In this study we saw the same reduction in breast cancer risk associated with a migraine history regardless of age." For the follow-up, the researchers also looked at women who did not drink, never smoked or took hormones. As Dr. Li notes, "We found the same association within each of those groups, suggesting that the association between migraine and reduced breast cancer risk may be independent of those other factors and may stand alone as a protective factor."

So what motivated the researchers to study the link between breast cancer and migraines? Dr. Li explains: "We know that migraine is definitely related to hormones and that's why we started looking at this in the first place." And he adds, "We have different ideas about what may be going on but it's unclear exactly what the biological mechanisms are." The researchers plan to conduct another investigation among the women who participated in the first study to get a better sense of the timing, types and severity of their migraines in order to determine if the data holds other clues.

News Release: Link between migraines and reduced breast cancer risk confirmed in follow-up study http://www.eurekalert.org/pub_releases/2009-07/fhcr-lbm070209.php July 9, 2009