07 November 2008

Migraines cut breast cancer risk

In a puzzling twist, women who have a history of migraine headaches are far less likely to develop breast cancer than other women, researchers say.

In a puzzling twist, women who have a history of migraine headaches are far less likely to develop breast cancer than other women, US researchers said on Thursday.

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% 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 Centre 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 oestrogen-receptor positive breast cancer, which is fuelled by oestrogen, and progesterone-receptor positive breast cancer, which is fuelled by progesterone.

Hormones also play a role in migraines, a brutal type of headache often accompanied by nausea, vomiting and heightened sensitivity to light and sound. Women are two to three times more likely than men to get migraines.

While it is not exactly clear why women with a history of migraines had a lower risk for breast cancer, Li and colleagues suspect hormones are playing a role.

How the study was done
"Women who have higher levels of oestrogen in their blood have higher levels of breast cancer," Li said. And he said migraines are often triggered by low levels of the hormone oestrogen, such as when oestrogen levels fall during a woman's menstrual cycle.

Women who get migraines "may have a chronically lower baseline oestrogen. That difference could be what is protective against breast cancer," Li said. For the study, Li and colleagues analysed data from two studies of 3 412 post-menopausal women in the Seattle area, 1 938 of whom had been diagnosed with breast cancer and 1 474 of whom had no history of breast cancer. Women in the study provided information on their migraine history.

They found women who had reported a clinical diagnosis of migraine had a 30% reduced risk of developing hormonally sensitive breast cancers. "Migraines are typically most severe among pre-menopausal women," Li said. "This study was all post-menopausal women."

He said that suggests the protective effect seen in women who get migraines may have a lasting effect at reducing breast cancer risk. "While these results need to be interpreted with caution, they point to a possible new factor that may be related to breast-cancer risk."

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. – (Reuters Health, November 2008)

Read more:
Oxygen therapies ease headaches
Aspirin cuts breast cancer risk


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Dr Elliot Shevel is a South African migraine surgery pioneer and the founder and medical director of The Headache Clinic in Johannesburg, Durban and Cape Town, South Africa. The Headache Clinic is a multidisciplinary practice dedicated to the diagnosis and treatment of Primary Headaches and Migraines. Dr Shevel is also the main author of all scientific publications generated by his team. He recently won a high level science debate in which he was able to prove that the current migraine diagnosis and classification is not based on data. Tertiary Education - Dr Shevel holds both Dental and Medical degrees, and practises as a specialist Maxillo-facial and Oral Surgeon. Follow the Headache Clinic on Twitter@HeadacheClinic.

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