Thyroid condition for headache patients?

"Our study is one of the largest studies published to date suggesting that headache disorders are a risk factor for the future development of hypothyroidism," explains lead author.

Researchers looked at data from 8,412 people enrolled in the Fernald Medical Monitoring Program (FMMP), a 20-year medical monitoring project designed to examine health outcomes of residents living near a former uranium processing plant in Crosby Township, Ohio, 18 miles northwest of Cincinnati.

They found that residents living near Fernald with pre-existing headache disorders had a 21 percent increased risk of developing new onset hypothyroidism while those with possible migraine showed an increased risk of 41 percent, says the author.

The data showed that those with migraine had the highest likelihood of developing hypothyroidism, which could suggest that persons with migraine are particularly susceptible to this disorder, explains the author. Migraine affects about 12 percent of the U.S. population and hypothyroidism typically impacts about 2 percent of Americans, author says. Though rarely life-threatening, migraine and hypothyroidism both lead to decreased quality of life if not treated adequately.

.The study results are consistent with past studies showing hypothyroidism to be more common in those with migraine or other headache disorders, but there are differences in how this study was designed compared to previous ones, says the author.

"We have a very large sample size and we have measurements of thyroid hormones at different time points throughout the study. We identified people with headache disorders and we followed them forward in time. It is a much stronger study than studies just looking at the association at one point in time," says the author. "We also followed these persons for 12 years on average."

The researchers found that female gender, increasing age, obesity and hypothyroid-inducing medications were associated with new onset hypothyroidism, says co-investigator and professor in the Department of Environmental Health at the University of Cincinnati. The findings from the study are consistent with previous studies.

Andrew Martin says there are several proposed mechanisms that might explain the association between headache disorders and hypothyroidism. Headache disorders activate the immune system, which could predispose to the future development of hypothyroidism. In addition, stress induced by headache disorders could increase its likelihood. Other environmental or genetic factors could be at play as well, explains the author.

It is unknown how these two disorders interact with one another. "It is possible that the development of hypothyroidism in a headache patient might further increase the frequency of headache as past studies have found that treatment of hypothyroidism reduces the frequency of headache," according to the author. "Regardless, physicians should be more vigilant in testing for hypothyroidism in persons with headache disorders."