Girls who get migraines appear more likely than their peers to gain extra weight during adulthood, scientists say.
They found that 40% of women with childhood migraines had added at least 9kg since age 18, compared to 30% of women who never had these throbbing headaches. Migraines have been linked to obesity before, but the new results held up even after adjusting for women's weight during adolescence.
It's possible that the pain, at times accompanied by nausea and vomiting, makes women eat differently or alter their physical activity, but the study wasn't designed to answer that. Still, it does hint that weight and migraines may somehow fuel each other, said Michelle A. Williams, of the University of Washington in Seattle, who led the work.
Pregnancy and migraines
Williams and colleagues analysed data on more than 3,700 women who were participating in another study on pregnancy outcomes.
They asked each woman what her weight and height were at age 18 and just before she got pregnant, and whether she had ever been told by her doctor that she had migraines.
More than one out of every six women said they had been diagnosed with migraine, a common problem among women that costs the US some $20 billion (about R140 billion) annually in lost productivity and medical care.
Among normal-weight women, about 17% had a migraine diagnosis, compared to 25% of obese women. After ruling out other factors, such as high blood pressure and smoking, migraine risk was still higher among heavy women and rose with weight.
Doubling the odds
"Relative to normal weight women, severely obese women have more than a doubling in odds of migraine," Williams said.
While relying on the women's memory is a clear limitation of the study, the results support earlier research, showing a link between weight and headaches in children and young adults (although the link appears to weaken as women get older).
For instance, one 2009 study found that heavy children who lost weight while receiving treatment for headaches had a greater reduction in headache frequency compared to children whose weight remained stable or increased.
"I would endorse the advice offered by the Centres for Disease Control and Prevention that promotes a lifestyle that includes healthy eating, regular physical activity, and avoidance of adult weight gain," said Williams, adding that more research is needed.
(Reuters Health, Frederik Joelving, February 2010)