Two methodologically identical national surveys in the United States conducted 10 years apart show that the prevalence and distribution of migraine have remained stable over the last decade. Migraine-associated disability remains substantial and pervasive. The number of migraineurs has increased from 23.6 million in 1989 to 27.9 million in 1999 commensurate with the growth of the population. Migraine is an important target for public health interventions because it is highly prevalent and disabling.

Abstract-Objectives: 1) To reassess the prevalence of migraine in the United States; 2) to assess patterns of migraine treatment in the population; and 3) to contrast current patterns of preventive treatment use with recommendations for use from an expert headache panel. Methods: A validated self-administered headache questionnaire was mailed to 120,000 US households, representative of the US population. Migraineurs were identified according to the criteria of the second edition of the International Classification of Headache Disorders. Guidelines for preventive medication use were developed by a panel of headache experts. Criteria for consider or offer prevention were based on headache frequency and impairment. Results: We assessed 162,576 individuals aged 12 years or older. The 1-year period prevalence for migraine was 11.7% (17.1% in women and 5.6% in men). Prevalence peaked in middle life and was lower in adolescents and those older than age 60 years. Of all migraineurs, 31.3% had an attack frequency of three or more per month, and 53.7% reported severe impairment or the need for bed rest. In total, 25.7% met criteria for "offer prevention," and in an additional 13.1%, prevention should be considered. Just 13.0% reported current use of daily preventive migraine medication. Conclusions: Compared with previous studies, the epidemiologic profile of migraine has remained stable in the United States during the past 15 years. More than one in four migraineurs are candidates for preventive therapy, and a substantial proportion of those who might benefit from prevention do not receive it.

Objective.-A population-based survey was conducted in 1999 to describe the patterns of migraine diagnosis and medication use in a representative sample of the US population and to compare results with a methodologically identical study conducted 10 years earlier.Methods.-A survey mailed to a panel of 20 000 US households identified 3577 individuals with severe headache meeting a case definition for migraine based on the International Headache Society (IHS) criteria. Those with severe headache answered questions regarding physician diagnosis and use of medications for headache as well as headache-related disability.Results.-A physician diagnosis of migraine was reported by 48% of survey participants who met IHS criteria for migraine in 1999, compared with 38% in 1989. A total of 41% of IHS-defined migraineurs used prescription drugs for headaches in 1999, compared with 37% in 1989. The proportion of IHS-defined migraineurs using only over-the-counter medications to treat their headaches was 57% in 1999, compared with 59% in 1989. In 1999, 37% of diagnosed and 21% of undiagnosed migraineurs reported 1 to 2 days of activity restriction per episode ( P Ͻ .001); 38% of diagnosed and 24% of undiagnosed migraineurs missed at least 1 day of work or school in the previous 3 months ( P Ͻ .001); 57% of diagnosed and 45% of undiagnosed migraineurs experienced at least a 50% reduction in work/school productivity ( P Ͻ .001).Conclusions.-Diagnosis of migraine has increased over the past decade. Nonetheless, approximately half of migraineurs remain undiagnosed, and the increased rates of diagnosis of migraine have been accompanied by only a modest increase in the proportion using prescription medicines. Migraine continues to cause significant disability whether or not there has been a physician diagnosis. Given the availability of effective treatments, public health initiatives to improve patterns of care are warranted.Key words: migraine, headache, diagnosis, American Migraine Study ( Headache 2001;41:638-645) Migraine is a common and often debilitating condition that affects 28 million Americans, approximately 18% of women and 6% of men in the United States.1,2 Migraine is a major cause of absenteeism from and decreased productivity at work and demonstrably reduces health-related quality of life.3-6 The condition costs American employers approximately $13 billion per year. 7Despite its pervasiveness and association with significant disability, migraine has historically been underrecognized and undertreated. In the American Migraine Study conducted in 1989, only 16% of migraineurs identified by questionnaire had consulted a physician for headache in the previous year, and only

Background.-Although headache is a common emergency department (ED) chief complaint, the role of the ED in the management of primary headache disorders has rarely been assessed from a population perspective. We determined frequency of ED use and risk factors for use among patients suffering severe headache.Methods.-As part of the American Migraine Prevalence and Prevention study, a validated self-administered questionnaire was mailed to 24,000 severe headache sufferers, who were randomly drawn from a larger sample constructed to be sociodemographically representative of the US population. Participants were asked a series of questions on headache management, healthcare system use, sociodemographic features, and number of ED visits for management of headache in the previous 12 months. In keeping with the work of others, "frequent" ED use was defined as a particpant's report of 4 or more visits to the ED for treatment of a headache in the previous 12 months. Headaches were categorized into specific diagnoses using a validated methodology.Results.