. . . . Epidemiology of Headache. The most common pain problem seen in family practice10 million office visits each year in the U.S.Direct medical and medication costs of migraine may reach $10 billion per yearIndirect costs estimated at $5 to $7 billion per year. Epidemiology. Estimated 28 million AmericansAMS II (American Migraine Study, 1999)12.6 % prevalence (18% women, 6.5% men)1 in 4 households has a least 1 migraineurApproximately 50% remain undiagnosed.