K. Hagen

The global burden of headache: a documentation of headache prevalence and disability worldwide.

This study, which is a part of the initiative Lifting The Burden: The Global Campaign to Reduce the Burden of Headache Worldwide, assesses and presents all existing evidence of the world prevalence and burden of headache disorders. Population-based studies applying International Headache Society criteria for migraine and tension-type headache, and also studies on headache in general and chronic daily headache, have been included. Globally, the percentages of the adult population with an active headache disorder are 46% for headache in general, 11% for migraine, 42% for tension-type headache and 3% for chronic daily headache. Our calculations indicate that the disability attributable to tension-type headache is larger worldwide than that due to migraine. On the World Health Organizations ranking of causes of disability, this would bring headache disorders into the 10 most disabling conditions for the two genders, and into the five most disabling for women.

Epidemiology of headache in Europe

The present review of epidemiologic studies on migraine and headache in Europe is part of a larger initiative by the European Brain Council to estimate the costs incurred because of brain disorders. Summarizing the data on 1‐year prevalence, the proportion of adults in Europe reporting headache was 51%, migraine 14%, and ‘chronic headache’ (i.e. ≥15u2003days/month or ‘daily’) 4%. Generally, migraine, and to a lesser degree headache, are most prevalent during the most productive years of adulthood, from age 20 to 50u2003years. Several European studies document the negative influence of headache disorders on the quality of life, and health‐economic studies indicate that 15% of adults were absent from work during the last year because of headache. Very few studies have been performed in Eastern Europe, and there are also surprisingly little data on tension‐type headache from any country. Although the methodology and the quality of the published studies vary considerably, making direct comparisons between different countries difficult, the present review clearly demonstrates that headache disorders are extremely prevalent and have a vast impact on public health. The data collected should be used as arguments to increase resources to headache research and care for headache patients all over the continent.

Depression and anxiety disorders associated with headache frequency. The Nord-Trøndelag Health Study.

The aim of this large cross‐sectional population‐based study was to examine the association between migraine, non‐migrainous headache and headache frequency with depression, and anxiety disorders. From 1995 to 1997, all 92u2003566 inhabitants aged 20u2003years and above in Nord‐Trøndelag County in Norway were invited to participate in the Nord‐Trøndelag Health Study (‘Helseundersøkelsen i Nord‐Trøndelag’u2003= HUNT‐2). A total of 64u2003560 participated, whereof 51u2003383 subjects (80%) completed a headache questionnaire that was included. Of these 51u2003383 individuals, 47u2003257 (92%) completed the depression subscale items and 43u2003478 (85%), the anxiety subscale items of the Hospital Anxiety and Depression Scale (HADS). Associations were assessed in multivariate analyses, estimating prevalence odds ratios (OR) with 95% confidence intervals (CI). Depression and anxiety disorders as measured by HADS, were significantly associated with migraine (ORu2003=u20032.7, 95% CI 2.3–3.2; ORu2003=u20033.2, 95% CI 2.8–3.6) and non‐migrainous headache (ORu2003=u20032.2, 95% CI 2.0–2.5; ORu2003=u20032.7, 95% CI 2.4–3.0) when compared with headache‐free individuals. The association was stronger for anxiety disorders than for depression. The ORs for depression and anxiety disorders amongst both migraine and non‐migrainous sufferers increased with increasing headache frequency. Depression and anxiety disorders are associated with both migraine and non‐migrainous headache, and this association seems more dependent on headache frequency than diagnostic category.

Prevalence of migraine and non‐migrainous headache—head‐HUNT, a large population‐based study

The objective of this study was to estimate the 1-year prevalence of the following categories of headache; migraine, non-migrainous headache, frequent headache (> 6 days/month), and chronic headache (> 14 days/month). Between 1995 and 1997, all 92 566 inhabitants 20 years and older in Nord-Trøndelag county in Norway were invited to a comprehensive health study. Out of 64 560 participants, a total of 51 383 subjects (80%) completed a headache questionnaire. The overall age-adjusted 1-year prevalence of headache was 38% (46% in women and 30% in men). The prevalence of migraine was 12% (16% in women and 8% in men), and for non-migrainous headache 26% (30% in women and 22% in men). For frequent headache (> 6 days per month) and for chronic headache (> 14 days per month), the prevalence was 8% and 2%, respectively. Women had a higher prevalence than men in all age groups and for all headache categories. Prevalence peaked in the fourth decade of life for both men and women, except for ‘frequent non-migrainous headache’, which was nearly constant across all age groups in both genders. In accordance with findings in other western countries, we found that headache suffering, including migraine, was highly prevalent, especially in younger women.

Analgesic use: A predictor of chronic pain and medication overuse headache The Head–HUNT Study

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The co‐occurrence of headache and musculoskeletal symptoms amongst 51 050 adults in Norway

We have evaluated the association between headache and musculoskeletal symptoms in a large cross‐sectional population‐based study. Between 1995 and 1997, all 92u2003566 adults in Nord‐Trøndelag County in Norway were invited to participate in a health survey. A total of 51u2003050 (55%) responded to questions concerning headache and musculoskeletal symptoms. Both migraine and non‐migrainous headache were strongly associated with musculoskeletal symptoms. However, frequency of headache had a higher impact than headache diagnosis on this association. Thus, the prevalence of chronic headache (headache >14u2003days/month) was more than four times higher (ORu2003=u20034.6; 95% CI 4.0–5.3) in the group of individuals with musculoskeletal symptoms than in those without. Individuals with neck pain were more likely to suffer from headache as compared with those with musculoskeletal symptoms in other restricted areas. In conclusion, there was a strong association between chronic headache and musculoskeletal symptoms, which may have implications for the choice of treatment.

Analgesic overuse among subjects with headache, neck, and low-back pain

Objectives: To examine the prevalence of chronic headache (≥15 days/month) associated with analgesic overuse in relation to age and gender and the association between analgesic overuse and chronic pain (i.e., migraine, nonmigrainous headache, neck and low-back pain). Methods: In the Nord–Trøndelag Health Study 1995 to 1997 (HUNT-2), a total of 51,383 subjects responded to headache questions (Head-HUNT), of which 51,050 completed questions related to musculoskeletal symptoms and 49,064 questions regarding the use of analgesics. Results: The prevalence of chronic headache associated with analgesic use daily or almost daily for ≥1 month was 1% (1.3% for women and 0.7% for men) and for analgesic overuse duration of ≥3 months 0.9% (1.2% for women and 0.6% for men). Chronic headache was more than seven times more likely among those with analgesic overuse (≥1 month) than those without (odds ratio [OR] = 7.5, 95% CI: 6.6 to 8.5). Upon analysis of the different chronic pain subgroups separately, the association with analgesic overuse was strongest for chronic migraine (OR = 10.3, 95% CI: 8.1 to 13.0), intermediate for chronic nonmigrainous headache (OR = 6.2, 95% CI: 5.3 to 7.2), and weakest for chronic neck (OR = 2.6, 95% CI: 2.3 to 2.9) and chronic low-back (OR = 3.0, 95% CI: 2.7 to 3.3) pain. The association became stronger with increasing duration of analgesic use for all groups and was most evident among those with headache, especially those with migraine. Conclusions: Chronic headache associated with analgesic overuse is prevalent and especially chronic migraine is more strongly associated with frequent intake of analgesics than other common pain conditions like chronic neck and chronic low-back pain.

Head‐HUNT: validity and reliability of a headache questionnaire in a large population‐based study in Norway

We have assessed the validity and reliability of a self-administered headache questionnaire used in the Nord-Trøndelag Health Survey 1995-97 (HUNT) in Norway, by blindly comparing questionnaire-based headache diagnoses with those made in a clinical interview of a sample of the participants. Restrictive questionnaire-based diagnostic criteria for migraine, assessed according to modified criteria of the International Headache Society, performed excellently in selecting definite migraine patients (100% positive predictive value). The best agreement concerning migraine diagnoses was achieved by using a liberal set of criteria (k 0.59). Similar agreement was found evaluating patient status as headache sufferers, and as sufferers from frequent headaches (>6 days per month) (k 0.57 and 0.50, respectively). The k values of nonmigrainous headache and chronic headache (>14 days per month) were 0.43 and 0.44, respectively. The results suggest that our self-administered questionnaire may be suitable in identifying a population with definite migraine, and the questionnaire is an acceptable instrument in determining the prevalence in Nord-Trøndelag of headache sufferers, migraine, non-migrainous headache, and frequent or chronic headache sufferers.

Low Socio-Economic Status is Associated with Increased Risk of Frequent Headache: A Prospective Study of 22718 Adults in Norway

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 22 685 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 ≥ 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.

Headache prevalence related to smoking and alcohol use. The Head‐HUNT Study

The aim of this study was to examine a possible association between smoking, alcohol and headache in a large population‐based cross‐sectional study. A total of 51u2003383 subjects completed a headache questionnaire and constituted the ‘Head‐HUNT’ Study. Questionnaire‐based information on smoking was available in 95% and on alcohol in 89% of the individuals. Associations were assessed in multivariate analyses, estimating prevalence odds ratios (ORs) with 95% confidence intervals (CI). Prevalence rates for headache were higher amongst smokers compared with never smokers, most evident for those under 40u2003years smoking more than 10 cigarettes per day (OR 1.5, 95% CI 1.3–1.6). Passive smoking was also associated with higher headache prevalence. For alcohol use, there was a tendency of decreasing prevalence of migraine with increasing amounts of alcohol consumption compared with alcohol abstinence. Only with regard to symptoms indicating alcohol overuse, a positive association with frequent headache was found. The association between headache and smoking found in the present study raises questions about a causal relationship, e.g. that smoking causes headache or that it allays stress induced by headache. The observed negative association between migraine and alcohol consumption is probably explained by the headache precipitating properties of alcohol.