Migraine Headaches, Sex Hormones Linked
Finding From Dutch Study of Male-to-Female Sex Change Patients
Aug. 20, 2004 -- A small group of Dutch male-to-female sex-change patients may have helped unravel some of the mystery of migraine headaches.
Scientists already knew that women report getting migraines three times as often as men. But what explains the gender difference?
Thinking that sex hormones might play a role, Tamara Pringsheim, MD, of the University of Toronto teamed with Dutch colleagues at Amsterdam's Gender Team Clinic to study the idea.
That's where the Dutch sex-change patients come in.
Fifty male-to-female sex-change patients being treated at the clinic took part in the study. All were taking anti-androgen hormones to suppress male sex characteristics and estrogens to induce female sex characteristics such as breast development.
They gave Pringsheim and her colleagues a unique window on gender and migraines by answering questions about their headaches' frequency, duration, intensity, location, symptoms, and related visual phenomena.
The study is published in the journal Neurology
Thirteen of the 50 (26%) met criteria for migraine headaches or probable migraine headaches.
Twenty-two (44%) had "tension-type" headaches, which are milder than migraine headaches and have a nonpulsating pain, and 15 (30%) didn't report any headaches.
The rate of migraine headaches among the sex-change patients was similar to the rate of migraines among Dutch women.
Nearly 25% of females in the Netherlands develop migraines, according to a separate study, which also showed migraines only affect 7.5% of Dutch men not taking anti-androgens and estrogens.
There are several possible explanations for the findings, including brain differences, gender roles, and the stress of undergoing sex change procedures, say the researchers.
But more likely, the patients' hormone therapies affected their levels of nitric oxide, a chemical that widens blood vessels and increases blood flow. It is a known migraine trigger influenced by estrogen and anti-androgen treatment.
A standard migraine is bad enough, but along with it can come an "aura" -- visual phenomena such as flashing lights, zigzag patterns, or dark spots before migraines start.
Of the migraine-affected transsexuals, 54% experienced migraine aura before the onset of their headaches.
Aura has also been linked to estrogen treatment. People who develop migraine aura while taking estrogen replacement therapy stop getting the aura after lowering their estrogen dose, write the researchers.
More work is needed to explore the possible connection between sex hormones and migraines.