The Burden of Headache
Headache disorders are among the most common of all health disorders. Their lifetime prevalence in many populations is over 90%. In any single year, almost half (47%) of all adults have direct personal experience of at least one headache disorder [reference 1].
Surprisingly, therefore, the epidemiology of headache disorders is still only partly documented. In the past, population-based studies have mostly focused on migraine, which is neither the most common nor the most disabling headache disorder. Tension-type headache is more common, while any of the headaches occurring on more days than not are generally more disabling. But these have received less attention. Furthermore, relatively few population-based studies have been conducted in low-income countries.
Nevertheless, and despite regional variations, there can be no doubt that headache disorders are highly prevalent everywhere. They affect people of all ages, races, income levels and geographical areas.
Migraine probably affects 20% of adults worldwide (the proportion is still being assessed). A three-times higher rate in women is hormonally-driven. Migraine is less common in children and in the elderly. Available figures suggest that 3,000 migraine attacks occur every day for each million of the general population [reference 2].
Episodic tension-type headache is the most common headache disorder. Worldwide there is much variation in its prevalence, with an average of 42% [reference 1], rather higher in women than in men. Chronic tension-type headache affects 1–3% of adults [reference 1].
Medication-overuse headache affects 1-2% of populations where it has been measured [reference 3], women more than men, and some children also.
Headache disorders do not shorten life. This is one reason why they are so poorly acknowledged. On the other hand, they impose pain and personal suffering, which may be substantial, damage quality of life and cause financial losses. Above all, headache disorders are disabling. Worldwide, migraine on its own is the cause of almost 3% of all disability due to illness, according to the most recent Global Burden of Disease Study [reference 4]. Collectively, headache disorders are the 3rd highest cause of disability in the world [reference 5].
All of these effects of migraine are within attacks. In addition, repeated unpleasant attacks can induce constant fear of the next. This harms family and social life and employment, and damages quality of life [reference 6]. Headache often results in cancellation of social activities while, at work, people who suffer frequent attacks are likely to be seen as unreliable – which they may be – or unable to cope. This can reduce the likelihood of promotion and undermine career and financial prospects [reference 6].
While those actually affected by headache disorders bear much of their burden, they do not carry it all. Employers, fellow-workers, family and friends may have to take on work and duties that headache sufferers cannot perform. Because headache disorders are most troublesome in the productive years (late teens to 50s), estimates of their financial cost to society are enormous. Migraine alone is the cause of an estimated 400,000 lost days from work or school every year per million of the population in developed countries [reference 2]. In the EU, the total annual cost of all headache has recently been estimated at €155 billion [reference 7].
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"No-one should think that the humanitarian burdens imposed by headache disorders weigh less in developing countries because they are less evident."
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Not so much is known about the public-health aspects of headache disorders in poorer countries. The huge financial costs of headache focus attention on the developed world where money is persuasive. Costs to society of lost work-time may be less where labour costs are lower, but the burdens on people who are unable to work or care for their children can still be severe. No-one should think that the humanitarian burdens of headache – not only pain, suffering and disability but also the many secondary burdens of lifestyle compromises, damaged relationships and lost opportunities – weigh less elsewhere because they are less evident. Poverty and its consequences of poor sanitation and infectious diseases may seem to be of overwhelming priority in many low-income countries, but why should headache and these burdens it imposes be any less disagreeable in the presence of hunger and other illness?
In summary, while headache is rarely a sign of serious illness, the public-health importance of these headache disorders lies in these personal and societal burdens of pain, disability, damaged quality of life and financial cost.
References
1. Stovner L et al. The global burden of headache: a documentation of headache prevalence and disability worldwide. Cephalalgia 2007; 27: 193-210. [view document]
2. Steiner TJ et al. The prevalence and disability burden of adult migraine in England and their relationships to age, gender and ethnicity. Cephalalgia 2003; 23: 519-527.
3. Westergaard ML et al. Definitions of medication-overuse headache in population-based studies and their implications on prevalence estimates: a systematic review. Cephalalgia 2014; 34: 409-425.
4. Vos T et al. Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012; 380: 2163-2196.
5. Steiner TJ et al. Headache disorders are third cause of disability worldwide. J Headache Pain 2015; 16: 58. [view document]
6. Lampl C et al. Interictal burden attributable to episodic headache: findings from the Eurolight project. J Headache Pain 2016; 17: 9. [view document]
7. Linde M et al. The cost of headache disorders in Europe: the Eurolight project. Eur J Neurol 2012; 19: 703-711.