Body mass index, migraine, migraine frequency and migraine features in women.

We evaluated the association of body mass index (BMI) with migraine and migraine specifics in a cross-sectional study of 63 467 women aged > or = 45 years, of whom 12,613 (19.9%) reported any history of migraine and 9195 had active migraine. Compared with women without migraine and a BMI < 23 kg/m(2), women with a BMI > or = 35 kg/m(2) had adjusted odds ratios (ORs) (95% confidence intervals) of 1.03 (0.95, 1.12) for any history of migraine. Findings were similar for active migraineurs. Women with a BMI of > or = 35 kg/m(2) had increased risk for low and high migraine frequency, with the highest estimate for women who reported daily migraine. Compared with women with the lowest associated risk (migraine frequency < 6 times/year; BMI between 27.0 and 29.9 kg/m(2)), women with a BMI > or = 35 kg/m(2) had an OR of daily migraine of 3.11 (1.12, 8.67). Among the women with active migraine, a BMI > or = 35 kg/m(2) was associated with increased risk of phonophobia and photophobia and decreased risk of a unilateral pain characteristic and migraine aura. Our data confirm previous findings that the association between BMI with migraine is limited to migraine frequency and specific migraine features.