Prevalence of migraine in Japan: a nationwide survey.

This study presents the first nationwide survey of migraine in Japan. A representative sample of 4029 subjects aged 15 years or older was selected from the Japanese population according to the quota method. A combination of telephone interview and mailed questionnaire methods was used. Diagnosis of migraine was based on the International Headache Society (IHS) Classification. The overall prevalence of migraine in the past year was 8.4%; 5.8% was migraine without aura and 2.6% was migraine with aura. Significant correlation was found between the prevalence of migraine and such variables as gender, age and district of residence. Doctor attendance rate was very low and 69.4% with migraine had never consulted a physician for headache. Yet, 74.2% complained that migraine headache impaired their daily activity significantly. Only 11.6% were aware that their headache was migraine and 56.9% were using only the over-the-counter drugs. The study revealed a comparably high prevalence of migraine in the general population of Japan compared with other countries. A genetic factor was speculated as the cause of regional difference in migraine prevalence.