Life style questionnaires. After making the baseline measurements, a standardized life style questionnaire will be provided to all patients who do not have a language problem. Age- and sex-matched healthy controls will be asked the same questions. The standardized questionnaire again requests demographic data such as age, gender, height, weight, abdominal circumference, traditional risk factors, medication history and other comorbidities. Newly-added demographic data include family history of risk factors, ABO type, marital status, living status, economic status, educational status and presence of pain and headache. Marital status is classified as married, single, divorced or widowed. Living status is classified as alone, with spouse, with family, or with non-family member. Economic status is classified into five categories (500 USD/month, 500~1500 USD/month, 1500~3000 USD/month, 3000~5000 USD/month and >5000 USD/month) and educational status is classified into six categories (none, <6 years, 6-9 years, 9-12 years, 12 years, >12 years). Questions about headaches are mainly focused on migraine: headache character, location, frequency, duration, aura, aggravating factors, medication history and family history. Only women will answer questions about obstetric history in terms of age at menarche and menopause (if participants have experienced them), use of oral contraceptives, history of hormone replacement therapy, and history of hysterectomy or oophorectomy. Women who have experienced pregnancy are asked about gravidity, number of children, years of births, mode of delivery, duration of maternal lactation, and number of miscarriages or abortions.