Chronic Migraine Prevalence,Disability, and Sociodemographic Factors: Results From the American Migraine Prevalence and Prevention Study

Objectives.— To estimate the prevalence and distribution of chronic migraine (CM) in the US population and compare the age‐ and sex‐specific profiles of headache‐related disability in persons with CM and episodic migraine. Background.— Global estimates of CM prevalence using various definitions typically range from 1.4% to 2.2%, but the influence of sociodemographic factors has not been completely characterized. Methods.— The American Migraine Prevalence and Prevention Study mailed surveys to a sample of 120,000 US households selected to represent the US population. Data on headache frequency, symptoms, sociodemographics, and headache‐related disability (using the Migraine Disability Assessment Scale) were obtained. Modified Silberstein–Lipton criteria were used to classify CM (meeting International Classification of Headache Disorders, second edition, criteria for migraine with a headache frequency of ≥15 days over the preceding 3 months). Results.— Surveys were returned by 162,756 individuals aged ≥12 years; 19,189 individuals (11.79%) met International Classification of Headache Disorders, second edition, criteria for migraine (17.27% of females; 5.72% of males), and 0.91% met criteria for CM (1.29% of females; 0.48% of males). Relative to 12 to 17 year olds, the age‐ and sex‐specific prevalence for CM peaked in the 40s at 1.89% (prevalence ratio 4.57; 95% confidence interval 3.13‐6.67) for females and 0.79% (prevalence ratio 3.35; 95% confidence interval 1.99‐5.63) for males. In univariate and adjusted models, CM prevalence was inversely related to annual household income. Lower income groups had higher rates of CM. Individuals with CM had greater headache‐related disability than those with episodic migraine and were more likely to be in the highest Migraine Disability Assessment Scale grade (37.96% vs 9.50%, respectively). Headache‐related disability was highest among females with CM compared with males. CM represented 7.68% of migraine cases overall, and the proportion generally increased with age. Conclusions.— In the US population, the prevalence of CM was nearly 1%. In adjusted models, CM prevalence was highest among females, in mid‐life, and in households with the lowest annual income. Severe headache‐related disability was more common among persons with CM and most common among females with CM.     

Prevalence and burden of migraine in the United States: data from the American Migraine Study II

OBJECTIVE: To describe the prevalence, sociodemographic profile, and the burden of migraine in the United States in 1999 and to compare results with the original American Migraine Study, a 1989 population-based study employing identical methods. METHODS: A validated, self-administered questionnaire was mailed to a sample of 20 000 households in the United States. Each household member with severe headache was asked to respond to questions about symptoms, frequency, and severity of headaches and about headache-related disability. Diagnostic criteria for migraine were based on those of the International Headache Society. This report is restricted to individuals 12 years and older. RESULTS: Of the 43 527 age-eligible individuals, 29 727 responded to the questionnaire for a 68.3% response rate. The prevalence of migraine was 18.2% among females and 6.5% among males. Approximately 23% of households contained at least one member suffering from migraine. Migraine prevalence was higher in whites than in blacks and was inversely related to household income. Prevalence increased from aged 12 years to about aged 40 years and declined thereafter in both sexes. Fifty-three percent of respondents reported that their severe headaches caused substantial impairment in activities or required bed rest. Approximately 31% missed at least 1 day of work or school in the previous 3 months because of migraine; 51% reported that work or school productivity was reduced by at least 50%. CONCLUSIONS: 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.     

Probable migraine in the United States: results of the American Migraine Prevalence and Prevention (AMPP) study

Probable migraine (PM) is a prevalent migraine subtype fulfilling all but one criterion for migraine with or without aura. The aims of this study were: (i) to describe the epidemiology, medical recognition and patterns of treatment for PM in the USA; (ii) to compare the patterns of preventive PM treatment in the population with expert panel guidelines for preventive treatment. A validated self-administered headache questionnaire was mailed to a random sample of 120,000 US households. Subjects were classified as PM according to the second edition of the International Classification of Headache Disorders (ICHD-2). The questionnaire also assessed patterns of migraine treatment. Guidelines for preventive medication use were developed by a panel of headache experts, who used headache frequency and impairment to assess the need for preventive therapy and the gap between current and ideal use. Our sample consisted of 162 576 individuals aged > or = 12 years. The 1-year period prevalence of PM was 4.5% (3.9% in men and 5.1% in women). In women and men, prevalence was higher in middle life, between the ages of 30 and 59 years. The prevalence of PM was significantly higher in African-Americans than in Whites (female 7.4% vs. 4.8%; male 4.8% vs. 3.7%) and inversely related to household income. During their headaches, most (48.2%) had at least some impairment, while 22.1% were severely disabled. The vast majority (97%) of PM sufferers used acute treatments, although 71% usually treated with over-the-counter medication. Most PM sufferers (52.8%) never used a migraine-preventive treatment and only 7.9% were currently using preventive medication. According to the expert panel guidelines, prevention should be offered (16.9%) or considered (11.5%) for 28.4% of the PM sufferers in the survey. We conclude that PM is a frequent, undertreated, sometimes disabling disorder. It has an epidemiological profile similar to migraine. In contrast to migraine, which is less prevalent in African-Americans than in Whites, PM is more prevalent in African-Americans than in Whites. In the USA, many with PM do not receive adequate treatment.