Insulin sensitivity is impaired in patients with migraine, Italian
investigators report in the August issue of Cephalalgia. The finding
suggests "a role for insulin resistance in the comorbidity between
migraine and vascular diseases."

"Epidemiological studies have demonstrated that migraine patients
have a significantly increased risk of developing hypertension,
stroke and Raynaud's phenomenon (vascular comorbidity of migraine),"
Dr. Innocenzo Rainero from the Headache Centre at the University of
Turin told Reuters Health. "Furthermore, a recent study reported a
very high incidence of migraine, especially migraine with aura,
among obese women, linking migraine and body mass index."

At present, the biological mechanisms underlying the vascular
comorbidity of migraine are unknown, the investigator pointed out.

Dr. Rainero and colleagues studied insulin sensitivity (or insulin
resistance) in 30 young nonobese, nondiabetic, normotensive patients
with migraine and 15 age- and sex- matched healthy controls.

All subjects underwent a standard fasting oral glucose tolerance
test (OGTT), with plasma samples collected at 0, 30, 60, 90, 120,
and 180 minutes after glucose loading.

"Basal glucose and insulin concentrations were relatively similar
for both patients and controls," Dr. Rainero told Reuters
Health. "However, glucose concentrations at 90, 120, 180 minutes
were significantly higher in migraine patients than controls."
Moreover, insulin sensitivity was significantly altered in migraine
patients in comparison with controls.

"Our study provides a possible pathophysiological mechanism
explaining the vascular comorbidity of migraine and suggests that
strategies improving insulin sensitivity may be helpful in
migraine," Dr. Rainero said.

Regular physical activity reduces insulin resistance, he noted "and
should be explored as a potential therapeutic modality in migraine
care. In addition, several insulin sensitizing drugs are now
commercially available and these drugs could be tested in migraine
prophylaxis," the investigator added.

Cephalalgia 2005;25:593-597