The aim of this review was to summarize population-based studies reporting prevalence and/or incidence of chronic migraine (CM) and to explore variation across studies. A systematic literature search was conducted. Relevant data were abstracted and estimates were subdivided based on the criteria used in each study. Sixteen publications representing 12 studies were accepted. None presented data on CM incidence. The prevalence of CM was 0-5.1%, with estimates typically in the range of 1.4-2.2%. Seven studies used Silberstein-Lipton criteria (or equivalent), with prevalence ranging from 0.9% to 5.1%. Three estimates used migraine that occurred ≥15 days per month, with prevalence ranging from 0 to 0.7%. Prevalence varied by World Health Organization region and gender. This review identified population-based studies of CM prevalence, although heterogeneity across studies and lack of data from certain regions leaves an incomplete picture. Future studies on CM would benefit from an International Classification of Headache Disorders consensus diagnosis that is clinically appropriate and operational in epidemiological studies.

The aim of this study was to examine the prevalence of headache and primary headache disorders like migraine and tension-type headaches among adolescents, and to explore the differences in headache prevalence and frequency by gender and age. This cross-sectional study was conducted in Nord-Trøndelag county, Norway, during the years 1995-97. In total, 8984 (88%) out of 10 202 invited adolescents aged 12-19 years participated in the youth part of the Nord-Trøndelag Health Study [Helseundersøkelsen i Nord-Trøndelag (HUNT)]. The total study population in this study consisted of 8255 individuals after exclusion of invalid questionnaires and students outside the target range of 13-18 years of age. The students completed a comprehensive questionnaire, and one of the questions was whether the students had experienced any headaches during the last 12 months. In addition, 5847 of these students were also subject to an interview in which they were asked whether they had experienced recurring headaches during the last year and, if so, were they classified as migraine (MI), tension-type headache (TTH) or non-classifiable headache. In the total questionnaire-based population, 76.8% reported having had headaches during the last 12 months (69.4% boys and 84.2% girls). Among those who also were interviewed, 29.1% reported having recurrent headaches (21.0% boys and 36.5% girls). The overall 1-year prevalence of migraine was 7%, of tension-type headache 18%, and of non-classifiable headache 4.8%. Higher prevalence rates were found for girls in all age groups and for all headache categories. The overall frequency of recurrent headaches did not vary significantly with age, but girls had significantly more frequent headaches than boys. We concluded that headache in general, and recurrent primary headache disorders like migraine and tension-type headaches, are common somatic complaints among Norwegian adolescents, especially among girls.

Quantitative thresholds for discomfort and pain with monocular and binocular light stimuli were measured in 67 controls and 67 migraine patients (37 migraine with aura and 30 migraine without aura). Patients were more photophobic during attack than outside attack (p < 0.03), and they were more sensitive to light than controls even between attacks (p < or = 0.0001). We found no differences in light sensitivity between migraine with aura and migraine without aura (p > or = 0.93). Unilateral pain affected light sensitivity on both sides. When asked with a questionnaire, 74% of patients answered that they were sensitive to light outside attack and 100% were sensitive during attack. Pain thresholds were generally lower among sensitive than non-sensitive patients (p = 0.004), indicating some agreement between subjective opinion and objective measurements of photophobia. Photophobia seems to be an intrinsic property of migraineurs. It is increased by migraine pain, but seems to be unrelated to migraine characteristics such as nausea, severity of attacks, pain character and pain laterality.

In this placebo-controlled trial, eletriptan, at selected doses, demonstrated superior efficacy, onset of action and patient acceptability in the acute treatment of migraine when compared with oral sumatriptan and placebo.

Prevalence studies exploring the relation between socio-economic status (SES) and headache have shown conflicting results. This is the first prospective study analysing the relation between SES and risk of headache. A total of 22685 adults not likely to suffer from headache were classified by SES at baseline in 1984-1986, and responded to a headache questionnaire in a follow-up 11 years later (1995-1997). SES at baseline was defined by educational level, occupation, and income. The risk of frequent headache and chronic headache (>6, and > or =15 days/month, respectively) at follow-up was estimated in relation to SES. When defining SES by educational level or type of occupation, low status was associated with increased risk of frequent and chronic headache at follow-up. The risk of frequent and chronic headache decreased with increasing individual income, but only among men. We conclude that individuals with low SES had higher risk of frequent and chronic headache than people with high SES.