Improving quality in population surveys of headache prevalence, burden and cost: key methodological considerations
© Steiner et al.; licensee Springer. 2013
Received: 1 October 2013
Accepted: 14 October 2013
Published: 25 October 2013
Population-based studies of headache disorders are important. They inform needs assessment and underpin service policy for a set of disorders that are a public-health priority. On the one hand, our knowledge of the global burden of headache is incomplete, with major geographical gaps; on the other, methodological differences and variable quality are notable among published studies of headache prevalence, burden and cost.
The purpose here was to start the process of developing standardized and better methodology in these studies. An expert consensus group was assembled to identify the key methodological issues, and areas where studies might fail. Members had competence and practical experience in headache epidemiology or epidemiology in general, and were drawn from all WHO world regions. We reviewed the relevant literature, and supplemented the knowledge gathered from this exercise with experience gained from recent Global Campaign population-based studies, not all yet published. We extracted methodological themes and identified issues within them that were of key importance.
We found wide variations in methodology. The themes within which methodological shortcomings had adverse impact on quality were the following: study design; selection and/or definition of population of interest; sampling and bias avoidance; sample size estimation; access to selected subjects (managing and reporting non-participation); case definition (including diagnosis and timeframe); case ascertainment (including diagnostic validation of questionnaires); burden estimation; reporting (methods and results). These are discussed.
Epidemiological studies of headache are important. They enhance our understanding of its origins, patterns, aetiology and risk factors, so improving opportunities for treatment and prevention of headache. They inform needs assessment, underpin service policy and push for acceptance of headache disorders as a public-health priority. They gain in importance because headache disorders are themselves important, a fact greatly emphasized by the Global Burden of Disease Study 2010 (GBD2010) led by the Institute of Health Metrics and Evaluation, which placed headache disorders among the top ten causes of disability worldwide .
GBD2010 measured “burden” in terms of disability-adjusted life years (DALYs), a metric derived by summing years of life lost to premature mortality (YLLs) and years lost to disability (YLDs). Only the latter are relevant to headache disorders. These are undoubtedly useful concepts for making comparisons between diseases, informative especially for health policy formulation and health-care resource allocation, but they are narrow measures nonetheless. We use “burden of disease” to mean all the negative consequences of living with a disease, although in practice not all are measurable.
Our account of the global burden of headache is incomplete. The numerous published studies of headache prevalence, and the not so many of burden, are notably focused on the western world and on migraine . The Global Campaign against Headache has been active in redressing this [3–6], but the evidence adduced for GBD2010 had major gaps, especially in African, South-East Asia and Eastern Mediterranean Regions. In addition, methodological differences and variable quality have both been major factors influencing findings among the studies reviewed by Stovner et al. . While more population-based studies of headache disorders are certainly called for, the need for standardized – and better – methodology in such studies has long been evident [2, 7].
The purpose of this document, a product of the Global Campaign against Headache [7–9], is to start the process of meeting this need. In highlighting the key methodological issues, it draws attention to areas where studies may fail, despite commitment to them of much money and time. It concentrates on issues that relate specifically or are of particular relevance to headache; discussion of general epidemiological principles is avoided. Even more, the focus is on headache disorders of public-health interest: migraine and tension-type headache (TTH). Medication-overuse headache (MOH) is also included because, on present understanding, it arises only as a complication of a pre-existing headache disorder, usually migraine. Unquestionably, MOH contributes to public ill-health [8, 9].
The process was led by Lifting The Burden (LTB), a non-governmental organization conducting the Global Campaign against Headache in official relations with the World Health Organization (WHO) [10–13]. LTB assembled an expert consensus group (the co-authors), selecting members to bring experience and competence in headache epidemiology and/or epidemiology in general, to include WHO staff members with expertise in these fields, and, in pursuit of international and cross-cultural relevance, to have personal knowledge of all six WHO world regions.
We reviewed the relevant literature. Reviews of the world literature on headache epidemiology had been performed already, in earlier initiatives to document the prevalence and burden of headache [2, 14–16] and the methodological issues arising from their measurement . These reviews had been updated by LJS and TJS in the process of submitting evidence for GBD2010 . We supplemented the knowledge gathered from these with more recent experience gained from LTB-supported population-based studies: four completed in Russia , China , India  and Pakistan , and three others still in progress and not yet published in Saudi Arabia, Zambia and Ethiopia. We extracted methodological themes and, within these, identified the areas in which methodological shortcomings with detrimental effect on quality were evident.
The expert group first acted as a sounding board in this process, conducted initially by email, and then convened as a consensus group at a meeting in Trondheim in August 2011. Through critical review, we applied a process of item reduction and distillation, retaining only those themes and issues arising from them that we considered of key importance. Final consensus was achieved through further email exchanges.
As anticipated, we found wide variations in reported methodology. The themes within which, in our view, methodological shortcomings had adverse impact on quality were the following:
Selection and/or definition of population of interest;
Sampling and bias avoidance;
Sample size estimation;
Access to selected subjects (managing and reporting non-participation);
Case definition (including diagnosis and timeframe);
Case ascertainment (including diagnostic validation of questionnaires);
Reporting (methods and results).
Methodological themes from the literature review, and shortcomings detrimental to quality
Potential impact on quality
Inappropriately selected for overall purpose
Unsuited to secondary purpose(s)
Population of interest
Inappropriately selected for purpose
High or very high
Sampling method (including means of access)
Systematically bias generating
Moderate to high
Inadequate for purpose
Low to high
Excessively reducing sample size
Low to high
Moderate to high
High or very high
Not according to accepted diagnostic criteria
Moderate to high
High or very high
Applying inappropriate or undefined timeframe
High or very high
Not according to accepted diagnostic criteria
Moderate to high
Employing unvalidated diagnostic methods
Moderate to high
Low to moderate
Not adequately descriptive of methods
Low to high
Not adequately descriptive of results
Moderate to high
On study design, most studies were descriptive, estimating headache prevalence and/or burden, and had cross-sectional designs adequate for this purpose. An occasionally recurring methodological error seen in some of these was the reporting of “risk factors” despite that cross-sectional studies can provide evidence only of association, not causation [17, 18]. A few studies had more analytical aims, explicitly attempting to define causes of or risk factors for headache, and adopted appropriate case-control or cohort designs.
We found studies that had not correctly defined the population of interest for their purposes; instead they surveyed groups of people chosen more for convenience [19–21]. Often these were studies of patient populations. We did not make a register of the very poor studies that attempted to infer population prevalence from patient samples, although there were examples of this.
Not all studies adopted methods of sampling from the population of interest with due concern for bias avoidance. Among studies sampling by telephone, not all clearly recognized, or sought to quantify or manage, the risk of bias arising from uneven distribution of telephones across different age, gender and socioeconomic groups [22–39]. Among those making contact with households, either by telephone or visiting, not all explicitly avoided selection bias arising when the person interviewed was whoever happened to answer. Some studies did not adequately describe their sampling methods – how households or individuals were selected such that a selection probability could be assigned to them.
We found headache surveys with sample sizes clearly too small for their stated purposes. We did not register these. In many cases, sample sizes were greatly reduced by high levels of non-participation [40–45]. We found, more seriously because no remedy could be offered, other studies in which levels of participation were not reported [20, 21, 33, 37, 38, 46–79].
Access methods in published studies included visits to households and calls to telephones (land-line or mobile), usually in either case without prior warning (cold-calling). The methods were not always adequately described: in particular, accounts were rarely given of the management of apparently empty households or of unanswered telephone calls. Also used were access by mail or e-mail . Participation levels were invariably low in such studies, such that adequate management of selection bias was virtually impossible. Some studies summoned prospective participants to the interviewer [80, 81], again not always with adequate management of selection bias.
The great majority of published studies applied case definitions in some manner according to the criteria of ICHD-II  or the earlier ICHD-I . Not all did so in the same way: “migraine” in some included all of its subtypes (ICHD-II codes 1.1-1.6) but in others only migraine with or without aura (ICHD-II codes 1.1 and 1.2). The terms “migraine” and “tension-type headache” included both episodic and chronic forms of each, or were restricted to the episodic forms, with the chronic forms subsumed within the category of headache occurring on ≥15 days/month (often referred to as “chronic daily headache”). Several studies separately reported the prevalences of migraine and probable migraine [84–88], establishing case definitions implying these were distinct entities. A few studies did not explicitly follow ICHD-II or ICHD-I [78, 89–93]. As to timeframe, most studies reported 1-year prevalences. Some reported lifetime prevalence [26, 32, 37, 44, 49, 50, 54, 58],[64, 69, 70, 80, 81, 94–108] and others reported shorter timeframes [28, 31, 80, 81, 90, 109–112] (e.g., 3 months). A considerable number reported no timeframe [21, 39, 41, 42, 46, 51, 52, 57],[63, 66, 71, 73, 75–79, 92, 93, 108],[113–123].
Most studies used a two-stage procedure for case ascertainment: participants were first asked whether they had headache or not (screening question) and only those who did were posed the diagnostic questions. Most studies then applied structured diagnostic questionnaires. Usually these were explicitly “based on ICHD-II” (or ICHD-I), but many studies referred to “modifications” of these criteria without indicating what these were. Not all studies reported diagnostic validation. Some did but attempted validation among headache patients in clinic rather than in a sample drawn from the population of interest [5, 89, 124–126].
We found few studies conducting burden estimations that were both relevant and comprehensive [3–5, 40]. Many studies reported only prevalence; some reported symptom burden (usually in terms of frequency, intensity and duration); some included limited enquiry into functional impact (commonly using the migraine disability assessment (MIDAS) questionnaire ). A very few reported burden on others [41, 128] and four estimated societal economic impact [9, 129–131]. Only three [4, 5, 40] explicitly addressed the limitations of recall, a factor inherent in enquiries into burden over past periods of time (often three months).
All of these methodological shortcomings could be, and often were, compounded by deficiencies in quality of reporting.
In the following, under the various themes, we discuss the issues of concern and highlight how methodological shortcomings might have detrimental impact on study quality.
Most published studies used appropriate designs. This might have been because most were of headache prevalence, requiring simpler cross-sectional designs. There was a tendency in some to overstep the limitations of these designs, which cannot for example produce evidence of causation to identify risk factors. The few studies that explicitly set out to define causal or risk factors for headache recognized the need for case-control or cohort designs.
The population of interest
In headache research, the population of interest is usually the population of a whole country, because national data are needed for health policy, but there may be good reasons to study regions larger  or smaller  than a country. Depending on the aim of the study, sub-populations defined by additional characteristics may be perfectly legitimate subjects of study: specific age groups (e.g., adults of working age, adolescents, school or pre-school children); members of groups defined by ethnicity, culture or language; workers in certain trades or professions, or university students; people with another particular disease, etc. Headache patient populations on the other hand, while they are easily accessed, are rarely of interest: they are highly selected and, furthermore, the criteria by which they are selected (often self-selected) are generally indeterminable. A study of such populations tells little about, and cannot be extrapolated to, either the general population or any more broadly-defined population.
Sampling, and bias avoidance
It is rarely possible to survey everyone in the population of interest, and usually necessary to choose from that population a smaller, manageable sample of people to whom access is possible. Because the intention is to generalize the data from this sample to the whole population of interest, the essential requirement is that it should remain representative of the population of interest. “Representative” means similar to the population of interest in all properties of relevance to (i.e., likely to influence) the object of measurement (here, headache prevalence and/or burden). In the context of headache, representativeness clearly encompasses age and gender, which are known to affect headache prevalence, and probably should encompass socioeconomic class, employment status, area of habitation (rural or urban), ethnicity and possibly native language and/or tribal group.
Random sampling from the entire population of interest, either simple or stratified, depends upon chance to achieve representativeness, with likelihood of success dependent on sample size. In most cases, random sampling depends on the existence of some form of overview of the population: for example, census data, population registers or a map showing all households in an area to be sampled. Studies adopting this method usually sampled by telephone: an established methodology, offering cheap and easy access. In addition, this method is possible in the absence of a population overview such as a complete telephone directory through the technique of random digit-dialling (dialling area code(s) followed randomly by as many digits as are typical for phone numbers in the area(s)) . Telephone sampling can work well in countries where telephones (land-line or mobile) are both widespread and evenly distributed across different age, gender and socioeconomic groups; otherwise, it is open to serious selection bias.
Many studies employed some form of cluster sampling, usually selecting participants from a limited number of defined geographical areas (e.g., blocks or streets, or parts of villages), themselves chosen randomly. This method is logistically efficient when selected participants are to be visited. In countries with obligatory schooling, representative samples of children of school age can be obtained by selecting all, or a random sample, of the pupils of a representative sample of schools (a form of cluster sampling).
Generally, in headache studies, only one member of a family is selected. Members of families are similar genetically, share their environment and have common lifestyles; these factors effectively reduce variance if two or more are included. Special issues therefore arise when sampling is dependent upon contacts with households rather than single persons (e.g., calling door-to-door or by household telephone without prior warning). Within a household, certain types of person are more likely to stay at home, open the door or answer the phone: selection bias will inevitably arise when the person interviewed is whoever happens to answer.
Sample size determination
Margin of error (95% confidence interval) according to sample size
Sample size (N)
Margin of error (%)
A larger sample may be needed to estimate burden than to estimate prevalence, because burden is not distributed equally among cases: most of it is accounted for by a minority of those with the disorder. In a Swedish survey, for example, 27% of people with migraine reported 68% of all attacks . Among all people with migraine, TTH or MOH, the relatively few with MOH have the highest individual burden .
Participation and non-participation
Sampling merely selects intended subjects, who become participants only when accessed and engaged (which entails procuring their willing cooperation so that the enquiry can be completed). A high level of non-participation is potentially damaging to representativeness, although how much so depends on the factors responsible for it . Non-participation results mostly from outright refusal: a key factor in headache studies is that people with headache, having a personal interest, are more likely to participate, promoting a form of selection bias that can be highly misleading. Also in headache studies, non-participation is not a constant between important subgroups (e.g., young males are often least willing).
As an access method, visits to households permit face-to-face interviews, which is the most direct method of engagement, allowing physical examination where this is a necessary part of the enquiry. Telephone interviews are almost as direct, without allowing physical examination. Access by mail is cheap, and by e-mail even cheaper, but both methods presume the use of self-administered questionnaires (also cheap, but requiring a high degree of literacy). The lack of engagement with an interviewer provides no encouragement to respond and no opportunity for clarifications; participation rates are generally low, incomplete returns are common and selection bias is unavoidable because certain types of people are inherently less likely to reply. Summoning prospective participants to the interviewer is time-consuming for them and invites bias with regard to who are willing and have the time.
Caseness and ascertainment
In studies whose purpose is to assess headache prevalence, or describe its characteristics, case definition – what precisely is meant by “headache” (or its types and subtypes, when these are to be considered) – is of obvious and fundamental importance. The criteria of ICHD-II  are currently the common language of definition, and description, of headache disorders.
Caseness must have a timeframe. This said, inconsistent terminology in headache has arisen, largely because many headache disorders are chronic but with episodic manifestations. An “active headache disorder” is, by definition, characterized by the occurrence of symptoms within the previous year . Prevalence studies that adopt this definition of a case (i.e., an individual who reports at least one headache episode during that time) necessarily use a timeframe of 1 year and usually report the findings as “1-year prevalence”. Strictly speaking, these are estimates of the number of current cases (point prevalence). A different enquiry that defines a case only when symptoms are actually present (“headache now” or “headache yesterday” ) also estimates point prevalence, but of headache attacks or headache as a symptom rather than of a headache disorder. We found most studies reported 1-year prevalence. Other timeframes, especially lifetime prevalence, are relevant to particular purposes (e.g., genetic studies). Shorter timeframes (e.g., 3 months) are difficult to relate, whilst studies specifying no timeframe lack useful case definition.
The two-stage procedure for case ascertainment (only participants responding affirmatively to a screening question are posed the diagnostic questions) is time saving, but with a potential penalty: a negative answer to the screening question terminates further enquiry, even though it can be false.
For epidemiological purposes, diagnostic criteria are almost always built into a structured questionnaire, although this is not how diagnoses are usually made in clinic. ICHD-II criteria were not designed for epidemiological enquiry, and are not particularly well-suited to it. For several reasons, modifications of ICHD-II are almost invariably necessary. First, their strict application would require that all participants be personally interviewed and in many cases examined by a competent clinician. In most cases, even if possible, this would be a questionable use of resources. Second, ICHD-II criteria are expressed in technical language, and must be translated for lay participants without loss or distortion of meaning. Third, certain criteria distinguishing between migraine and TTH pose particular problems in epidemiological surveys, noted empirically in studies within the Global Campaign [3–5]. It has been found difficult to gather correct responses on headache duration, requiring patients to consider untreated attacks, which they may never have or last had long ago. There are no easy lay explanations of photo- and phonophobia, which are technical concepts, and it is even more difficult to specify what degrees of photo- and phonophobia fulfil migraine criteria in ICHD-II.
The separate reporting of prevalences of migraine and probable migraine (or TTH and probable TTH), as though these were distinct entities, is highly problematic. ICHD-II sets the general rule that, when all but one criterion for disorder X are met, the diagnosis is “probable X” (provided that not all criteria are met for another disorder Y, in which case the correct diagnosis is Y). This has an important purpose in clinical management, providing a basis for a treatment plan pending later diagnostic confirmation. In epidemiological surveys, later confirmation is not expected: initial diagnoses of probable X have no opportunity to be amended either to X or to another diagnosis. In the specific cases of migraine and TTH, diagnosis of the former depends upon the presence of specific features (e.g., nausea, vomiting, photophobia and phonophobia, aggravation by physical activity), while diagnosis of TTH depends essentially upon the absence of these same features. By ICHD-II rules, the presence of all but one feature of migraine is not consistent with a diagnosis of TTH, and must lead to a diagnosis of probable migraine. The same is true of probable TTH. Yet there are unavoidable uncertainties in questionnaire-based diagnoses, with the consequence that, according to ICHD rules, about half of such diagnoses are probable while, in validation studies conducted in sub-groups of the same populations, fewer than 10% of expert diagnoses are probable (unreported data from Ayzenberg et al. , Yu et al.  and Rao et al. ). It is difficult to see that the concept of “probable X” (as something distinct from “X”) serves any purpose in studies of population health.
Validation of the diagnostic questionnaire
Validation proves the diagnostic capability, in the population of interest, of the diagnostic questionnaire. It gains importance when modifications of ICHD-II criteria are adopted, which is almost always necessary (see above). It must, to achieve its purpose, be performed either in a separate sample of the population of interest, selected by identical methodology to the main sample, or in a randomly or consecutively selected sub-sample of participants in the main study. Headache patients in clinic are especially unrepresentative of any population of interest in terms of their headache disorders and, probably, a range of other relevant factors. They commonly have more knowledge of headache, and perform differently from non-clinic populations when answering questionnaires because they have rehearsed their histories.
Validation is not always possible. In countries where there are no headache experts, there is no gold standard available. In such cases only, going ahead without diagnostic validation may be justifiable, because the alternative is that research of public-health importance can never be commenced. What should then be avoided is the invention of a new and untested questionnaire, rather than adopt one that has at least been used previously and validated in multiple languages and cultures.
This area of enquiry is being developed by LTB in Global Campaign studies in Russia , China , India , Pakistan , Saudi Arabia, Zambia, Ethiopia, Nepal and Guatemala (not yet published). “Relevant” implies that measured burden must be attributable to headache, and not to any other cause (including comorbidity). Burden of headache has many different elements. “Comprehensiveness” requires that all are measured if a full account is needed. However, the purpose of the study can legitimately restrict the enquiry to specific elements (for example, financial burden ).
Some elements of burden are not quantifiable, but amenable only to qualitative (descriptive) analysis. In all cases of burden estimation (more so than for prevalence estimation because of the complexities of burden), the limitations of recall are an important factor in the generation of information bias.
Elements of burden
Symptom burden in common headache disorders arises from pain, and, in migraine, additionally from nausea, vomiting and photo- and/or phonophobia. While present, these symptoms may cause debility and prostration, and reduce functional ability. The consequences include inability to work. This secondary disability burden is magnified because headache is most common in people between their teens and 50-60 years of age – the productive years. Attached to disability may be a cost burden from lost pay. To the extent that this arises from lost wages, as a consequence of absenteeism, it is a relevant and important component of the burden of headache for many people. However, housewives and unemployed people may have no income to lose. In other cases, this cost is only a small part of the personal burden because it is largely borne by employers or insurers, contributing instead to the very high societal economic burden.
Headache attacks are unpleasant; people who experience them frequently worry about when the next may occur. They may identify triggers, and attempt to eliminate them by lifestyle compromise. Leisure activities may be cancelled or curtailed because of headache; when many social events have been cancelled, they are likely not to be planned in the first place. These are all elements of interictal burden, which may be sufficient to impair quality of life. The great importance of interictal burden lies in the fact that it is continuous, rather than present only during attacks occurring perhaps every 30 days. This means both that it should not be ignored and that, if over-estimated, it will greatly distort overall burden quantification.
A consequence of recurring inability to work may be decreased probability of promotion, with failure to develop full career potential. A consequence of lost school-time may be reduced career opportunities. In both cases, the result is lower pay and impaired financial security. Over a lifetime, the cumulative burden of financial losses can be substantial.
A summary measure of overall individual burden is unlikely to be comprehensive, but the concept is attractive for its simplicity. Measures of quality of life are very non-specific, but comparison with a matched non-headache group may provide a useful indicator of burden expressed in very broad terms.
Burden on others, unaffected by headache themselves, arises in several ways. Employers and work colleagues carry part of it when paid-for work is not done: either the employer pays for nothing, or colleagues take on extra duties to make up. Family and friends lose the companionship they reasonably expect, but which is not given by a person shut away in a dark room. Children may not always be looked after. Partners and other family members may inherit increased shares of chores and responsibilities. They may acquire a carer burden, called to look after the person with headache. Carers, as well as the sufferer, can lose time from work.
Health-care resource consumption, when direct treatment costs for a condition affecting a large proportion of the population are reimbursed by a state-funded health system, is a substantial contributor to societal economic burden. But by far the greater part of the financial cost of headache is the indirect cost of absenteeism and reduced effectiveness at work [9, 130].
Reporting of methods and results
Methods can be assessed only according to how they are reported. While we found that methodological shortcomings were often compounded by deficiencies in quality of reporting, it might sometimes be the case (but this can never be known) that methods were better than the reporting of them indicated.
The same is true of results.
There is worldwide neglect of headache disorders as major causes of public ill-health, and inadequate responses to them in countries throughout the world . In this context, population-based studies of headache inform needs assessment and are the essential guide for provision of headache services and the commitment of appropriate resources to them. Quality assurance in the design, conduct and reporting of them is as important as in clinical trials, but this fact has not been well recognized. The literature reveals many issues, highlighted here, that require attention.
A full account of burden, which should underpin needs assessment, requires a rather detailed enquiry. The methodology is still under development.
The production, publication and dissemination of expert guidance, empirically tested, would be of major benefit – a large step towards improving quality in population surveys of headache prevalence, burden and cost. It is a necessary step in the path towards addressing these inadequate responses.
This article, as a Consensus Article from experts in the topic, has been reviewed internally among the Authors and Editorial Office.
International Headache Society, World Headache Alliance, Norwegian University of Science and Technology, Lifting The Burden.
- Vos T, Flaxman AD, Naghavi M, Lozano R, Michaud C, 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. 10.1016/S0140-6736(12)61729-2PubMedGoogle Scholar
- Stovner LJ, Hagen K, Jensen R, Katsarava Z, Lipton R, et al.: The global burden of headache: a documentation of headache prevalence and disability worldwide. Cephalalgia 2007, 27: 193–210. 10.1111/j.1468-2982.2007.01288.xPubMedGoogle Scholar
- Ayzenberg I, Katsarava Z, Mathalikov R, Chernysh M, Osipova V, et al.: The burden of headache in Russia: validation of the diagnostic questionnaire in a population-based sample. Eur J Neurol 2011, 18: 454–459. 10.1111/j.1468-1331.2010.03177.xPubMedGoogle Scholar
- Yu SY, Cao XT, Zhao G, Yang XS, Qiao XY, et al.: The burden of headache in China: validation of diagnostic questionnaire for a population-based survey. J Headache Pain 2011, 12: 141–146. 10.1007/s10194-011-0336-2PubMed CentralPubMedGoogle Scholar
- Rao GN, Kulkarni GB, Gururaj G, Rajesh K, Subbakrishna DK, et al.: The burden of headache disorders in India: methodology and questionnaire validation for a community-based survey in Karnataka State. J Headache Pain 2012, 13: 543–550. 10.1007/s10194-012-0474-1PubMed CentralPubMedGoogle Scholar
- Herekar AD, Herekar AA, Ahmad A, Uqaili UL, Ahmed B, et al.: The burden of headache disorders in Pakistan: methodology of a population-based nationwide study, and questionnaire validation. J Headache Pain 2013, 14: 73. 10.1186/1129-2377-14-73PubMed CentralPubMedGoogle Scholar
- Stovner LJ, Scher AI: Epidemiology of Headache. In The Headaches. 3rd edition. Edited by: Olesen JG, Ramadan PJ, Tfelt-Hansen NM, Welch P, MA K. Philadelphia: Lippincott Williams & Wilkins; 2005:17–26.Google Scholar
- Lanteri-Minet M, Duru G, Mudge M, Cottrell S: Quality of life impairment, disability and economic burden associated with chronic daily headache, focusing on chronic migraine with or without medication overuse: a systematic review. Cephalalgia 2011, 31: 837–850. 10.1177/0333102411398400PubMedGoogle Scholar
- Linde M, Gustavsson A, Stovner LJ, Steiner TJ, Barre J, et al.: The cost of headache disorders in Europe: the Eurolight project. Eur J Neurol 2012, 19: 703–711. 10.1111/j.1468-1331.2011.03612.xPubMedGoogle Scholar
- Steiner TJ: Lifting the burden: the global campaign against headache. Lancet Neurol 2004, 3: 204–205. 10.1016/S1474-4422(04)00703-3PubMedGoogle Scholar
- Steiner TJ: Lifting The Burden : the global campaign to reduce the burden of headache worldwide. J Headache Pain 2005, 6: 373–377. 10.1007/s10194-005-0241-7PubMed CentralPubMedGoogle Scholar
- Steiner TJ, Birbeck GL, Jensen R, Katsarava Z, Martelletti P, et al.: Lifting The Burden : the first 7 years. J Headache Pain 2010, 11: 451–455. 10.1007/s10194-010-0264-6PubMed CentralPubMedGoogle Scholar
- Steiner TJ, Birbeck GL, Jensen R, Katsarava Z, Martelletti P, et al.: The Global Campaign, World Health Organization and Lifting The Burden : collaboration in action. J Headache Pain 2011, 12: 273–274. 10.1007/s10194-011-0342-4PubMed CentralPubMedGoogle Scholar
- Stovner LJ, Zwart JA, Hagen K, Terwindt G, Pascual J: Epidemiology of headache in Europe. Eur J Neurol 2006, 13: 333–345. 10.1111/j.1468-1331.2006.01184.xPubMedGoogle Scholar
- Stovner L, Andrée C, On behalf of the Eurolight Steering Committee: Impact of headache in Europe: a review for the Eurolight project. J Headache Pain 2008, 9: 139–146. 10.1007/s10194-008-0038-6PubMed CentralPubMedGoogle Scholar
- Stovner LJ, Andrée C: Prevalence of headache in Europe: a review for the Eurolight project. J Headache Pain 2010, 11: 289–299. 10.1007/s10194-010-0217-0PubMed CentralPubMedGoogle Scholar
- Ohayon MM: Prevalence and risk factors of morning headaches in the general population. Arch Intern Med 2004, 164: 97–102. 10.1001/archinte.164.1.97PubMedGoogle Scholar
- Hagen K, Vatten L, Stovner LJ, Zwart JA, Krokstad S, et al.: Low socio-economic status is associated with increased risk of frequent headache: a prospective study of 22718 adults in Norway. Cephalalgia 2002, 22: 672–679. 10.1046/j.1468-2982.2002.00413.xPubMedGoogle Scholar
- Moens G, Johannik K, Verbeek C, Bulterys S: The prevalence and characteristics of migraine among the Belgian working population. Acta Neurol Belg 2007, 107: 84–90.PubMedGoogle Scholar
- Matuja WB, Mteza IB, Rwiza HT: Headache in a nonclinical population in Dar es Salaam, Tanzania. A community-based study. Headache 1995, 35: 273–276. 10.1111/j.1526-4610.1995.hed3505273.xPubMedGoogle Scholar
- Domingues RB, Kuster GW, Dutra LA, Santos JG: Headache epidemiology in Vitoria, Espirito Santo. Arq Neuropsiquiatr 2004, 62: 588–591. 10.1590/S0004-282X2004000400004PubMedGoogle Scholar
- Bassols Farres A, Bosch-Llonch F, Campillo-Grau M, Banos-Diez JE: An epidemiologic study of headache and its treatment in the general population of Catalonia. Rev Neurol 2002, 34: 901–908.PubMedGoogle Scholar
- Bigal ME, Liberman JN, Lipton RB: Age-dependent prevalence and clinical features of migraine. Neurology 2006, 67: 246–251. 10.1212/01.wnl.0000225186.76323.69PubMedGoogle Scholar
- Scher AI, Stewart WF, Liberman J, Lipton RB: Prevalence of frequent headache in a population sample. Headache 1998, 38: 497–506. 10.1046/j.1526-4610.1998.3807497.xPubMedGoogle Scholar
- Steiner TJ, Scher AI, Stewart WF, Kolodner K, Liberman J, 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. 10.1046/j.1468-2982.2003.00568.xPubMedGoogle Scholar
- Duckro PN, Tait RC, Margolis RB: Prevalence of very severe headache in a large US metropolitan area. Cephalalgia 1989, 15: 199–205.Google Scholar
- Kryst S, Scherl E: A population-based survey of the social and personal impact of headache. Headache 1994, 34: 344–350. 10.1111/j.1526-4610.1994.hed3406344.xPubMedGoogle Scholar
- Linet MS, Stewart WF, Celentano DD, Ziegler D, Sprecher M: An epidemiologic study of headache among adolescents and young adults. JAMA 1989, 261: 2211–2216. 10.1001/jama.1989.03420150061038PubMedGoogle Scholar
- Schwartz BS, Stewart WF, Lipton RB: Lost workdays and decreased work effectiveness associated with headache in the workplace. J Occup Environ Med 1997, 39: 320–327. 10.1097/00043764-199704000-00009PubMedGoogle Scholar
- Lipton RB, Scher AI, Kolodner K, Liberman J, Steiner TJ, et al.: Migraine in the United States: epidemiology and patterns of health care use. Neurology 2002, 58: 885–894. 10.1212/WNL.58.6.885PubMedGoogle Scholar
- Stewart WF, Ricci JA, Chee E, Morganstein D, Lipton R: Lost productive time and cost due to common pain conditions in the US workforce. JAMA 2003, 290: 2443–2454. 10.1001/jama.290.18.2443PubMedGoogle Scholar
- O’Brien B, Goeree R, Streiner D: Prevalence of migraine headache in Canada: a population-based survey. Int J Epidemiol 1994, 23: 1020–1026. 10.1093/ije/23.5.1020PubMedGoogle Scholar
- Pryse-Phillips W, Findlay H, Tugwell P, Edmeads J, Murray TJ, et al.: A Canadian population survey on the clinical, epidemiologic and societal impact of migraine and tension-type headache. Can J Neurol Sci 1992, 19: 333–339.PubMedGoogle Scholar
- Von Korff M, Stewart WF, Simon DJ, Lipton RB: Migraine and reduced work performance: a population-based diary study. Neurology 1998, 50: 1741–1745. 10.1212/WNL.50.6.1741PubMedGoogle Scholar
- Cheung RT: Prevalence of migraine, tension-type headache, and other headaches in Hong Kong. Headache 2000, 40: 473–479. 10.1046/j.1526-4610.2000.00071.xPubMedGoogle Scholar
- Roh JK, Kim JS, Ahn YO: Epidemiologic and clinical characteristics of migraine and tension-type headache in Korea. Headache 1998, 38: 356–365. 10.1046/j.1526-4610.1998.3805356.xPubMedGoogle Scholar
- Sakai F, Igarashi H: Prevalence of migraine in Japan: a nationwide survey. Cephalalgia 1997, 17: 15–22. 10.1046/j.1468-2982.1997.1701015.xPubMedGoogle Scholar
- Miranda H, Ortiz G, Figueroa S, Pena D, Guzman J: Prevalence of headache in Puerto Rico. Headache 2003, 43: 774–778. 10.1046/j.1526-4610.2003.03135.xPubMedGoogle Scholar
- Thomson AN, White GE, West R: The prevalence of bad headaches including migraine in a multiethnic community. N Z Med J 1993, 106: 477–480.PubMedGoogle Scholar
- Andrée C, Stovner LJ, Steiner TJ, Barré J, Katsarava Z, et al.: The eurolight project: the impact of primary headache disorders in Europe, description of methods. J Headache Pain 2011, 12: 541–549. 10.1007/s10194-011-0356-yPubMed CentralPubMedGoogle Scholar
- Clarke CE, MacMillan L, Sondhi S, Wells NE: Economic and social impact of migraine. QJM 1996, 89: 77–84. 10.1093/oxfordjournals.qjmed.a030141PubMedGoogle Scholar
- Colas R, Munoz P, Temprano R, Gomez C, Pascual J: Chronic daily headache with analgesic overuse: epidemiology and impact on quality of life. Neurology 2004, 62: 1338–1342. 10.1212/01.WNL.0000120545.45443.93PubMedGoogle Scholar
- Lee LH, Olness KN: Clinical and demographic characteristics of migraine in urban children. Headache 1997, 37: 269–276. 10.1046/j.1526-4610.1997.3705269.xPubMedGoogle Scholar
- Ho KH, Ong BK, Lee SC: Headache and self-assessed depression scores in Singapore University undergraduates. Headache 1997, 37: 26–30. 10.1046/j.1526-4610.1997.3701026.xPubMedGoogle Scholar
- Queiroz LP, Barea LM, Blank N: An epidemiological study of headache in Florianopolis, Brazil. Cephalalgia 2006, 26: 122–127. 10.1111/j.1468-2982.2005.00998.xPubMedGoogle Scholar
- Levy LM: An epidemiological study of headache in an urban population in Zimbabwe. Headache 1983, 23: 2–9.PubMedGoogle Scholar
- Dent W, Spiss H, Helbok R, Matuja W, Scheunemann S, et al.: Prevalence of migraine in a rural area in South Tanzania: a door-to-door survey. Cephalalgia 2004, 24: 960–966. 10.1111/j.1468-2982.2004.00775.xPubMedGoogle Scholar
- Winkler A, Dent W, Stelzhammer B, Kerschbaumsteiner K, Meindl M, et al.: Prevalence of migraine headache in a rural area of northern. Cephalalgia: Tanzania: a community-based door-to-door survey; 2009.Google Scholar
- King NJ, Sharpley CF: Headache activity in children and adolescents. J Paediatr Child Health 1990, 26: 50–54. 10.1111/j.1440-1754.1990.tb02379.xPubMedGoogle Scholar
- Barea LM, Tannhauser M, Rotta NT: An epidemiologic study of headache among children and adolescents of southern Brazil. Cephalalgia 1996, 16: 545–549. 10.1046/j.1468-2982.1996.1608545.xPubMedGoogle Scholar
- Sachs H, Sevilla F, Barberis P, Bolis L, Schoenberg B, et al.: Headache in the rural village of Quiroga, Ecuador. Headache 1985, 25: 190–193. 10.1111/j.1526-4610.1985.hed2504190.xPubMedGoogle Scholar
- Cruz ME, Cruz I, Preux PM, Schantz P, Dumas M: Headache and cysticercosis in Ecuador, South America. Headache 1995, 35: 93–97. 10.1111/j.1526-4610.1995.hed3502093.xPubMedGoogle Scholar
- Rondon J, Padron-Freytez A, Rada R: Prevalence of migraine among primary- and secondary-school students in Merida, Venezuela. Rev Panam Salud Publica 2001, 9: 73–77. 10.1590/S1020-49892001000200003PubMedGoogle Scholar
- Kececi H, Dener S: Epidemiological and clinical characteristics of migraine in Sivas, Turkey. Headache 2002, 42: 275–280. 10.1046/j.1526-4610.2002.02080.xPubMedGoogle Scholar
- Wang SJ, Fuh JL, Juang KD, Lu SR: Rising prevalence of migraine in Taiwanese adolescents aged 13–15 years. Cephalalgia 2005, 25: 433–438. 10.1111/j.1468-2982.2005.00873.xPubMedGoogle Scholar
- Cheng XM, Ziegler DK, Li SC, Dai QS, Chandra V, et al.: A prevalence survey of ’incapacitating headache’ in the People’s Republic of China. Neurology 1986, 36: 831–834. 10.1212/WNL.36.6.831PubMedGoogle Scholar
- Gourie-Devi M, Gururaj G, Satishchandra P, Subbakrishna DK: Prevalence of neurological disorders in Bangalore, India: a community-based study with a comparison between urban and rural areas. Neuroepidemiology 2004, 23: 261–268. 10.1159/000080090PubMedGoogle Scholar
- Abdul Jabbar M, Ogunniyi A: Sociodemographic factors and primary headache syndromes in a Saudi community. Neuroepidemiology 1997, 16: 48–52. 10.1159/000109670PubMedGoogle Scholar
- Zhao F, Tsay JY, Cheng XM, Wong WJ, Li SC, et al.: Epidemiology of migraine: a survey in 21 provinces of the People’s Republic of China, 1985. Headache 1988, 28: 558–565. 10.1111/j.1526-4610.1988.hed2808558.xPubMedGoogle Scholar
- Ayatollahi SM, Moradi F, Ayatollahi SA: Prevalences of migraine and tension-type headache in adolescent girls of Shiraz (southern Iran). Headache 2002, 42: 287–290. 10.1046/j.1526-4610.2002.02082.xPubMedGoogle Scholar
- Siddiqui SJ, Shamim SM, Hashmi AM: Prevalence and patterns of headache in school children in Karachi. J Pak Med Assoc 2006, 56: 215–217.PubMedGoogle Scholar
- Ando N, Fujimoto S, Ishikawa T, Teramoto J, Kobayashi S, et al.: Prevalence and features of migraine in Japanese junior high school students aged 12–15 yr. Brain Dev 2007, 29: 482–485. 10.1016/j.braindev.2007.01.003PubMedGoogle Scholar
- Stang PE, Osterhaus JT: Impact of migraine in the United States: data from the National Health Interview Survey. Headache 1993, 33: 29–35. 10.1111/j.1526-4610.1993.hed3301029.xPubMedGoogle Scholar
- Ziegler DK, Hassanein RS, Couch JR: Characteristics of life headache histories in a nonclinic population. Neurology 1977, 27: 265–269. 10.1212/WNL.27.3.265PubMedGoogle Scholar
- Michel P, Pariente P, Duru G, Dreyfus JP, Chabriat H, et al.: MIG ACCESS: a population-based, nationwide, comparative survey of access to care in migraine in France. Cephalalgia 1996, 16: 50–55. 10.1046/j.1468-2982.1996.1601050.xPubMedGoogle Scholar
- Henry P, Michel P, Brochet B, Dartigues JF, Tison S, et al.: A nationwide survey of migraine in France: prevalence and clinical features in adults. Cephalalgia 1992, 12: 229–237. 10.1046/j.1468-2982.1992.1204229.xPubMedGoogle Scholar
- Raieli V, Raimondo D, Cammalleri R, Camarda R: Migraine headaches in adolescents: a student population-based study in Monreale. Cephalalgia 1995, 15: 5–12. 10.1046/j.1468-2982.1995.1501005.xPubMedGoogle Scholar
- Mitsikostas DD, Tsaklakidou D, Athanasiadis N, Thomas A: The prevalence of headache in Greece: correlations to latitude and climatological factors. Headache 1996, 36: 168–173. 10.1046/j.1526-4610.1996.3603168.xPubMedGoogle Scholar
- Boru UT, Kocer A, Luleci A, Sur H, Tutkan H, et al.: Prevalence and characteristics of migraine in women of reproductive age in Istanbul, Turkey: a population based survey. Tohoku J Exp Med 2005, 206: 51–59. 10.1620/tjem.206.51PubMedGoogle Scholar
- Celik Y, Ekuklu G, Tokuc B, Utku U: Migraine prevalence and some related factors in Turkey. Headache 2005, 45: 32–36. 10.1111/j.1526-4610.2005.05007.xPubMedGoogle Scholar
- Zencir M, Ergin H, Sahiner T, Kilic I, Alkis E, et al.: Epidemiology and symptomatology of migraine among school children: Denizli urban area in Turkey. Headache 2004, 44: 780–785. 10.1111/j.1526-4610.2004.04145.xPubMedGoogle Scholar
- Dahlof C, Linde M: One-year prevalence of migraine in Sweden: a population-based study in adults. Cephalalgia 2001, 21: 664–671. 10.1046/j.1468-2982.2001.00218.xPubMedGoogle Scholar
- Akyol A, Kiylioglu N, Aydin I, Erturk A, Kaya E, et al.: Epidemiology and clinical characteristics of migraine among school children in the Menderes region. Cephalalgia 2007, 27: 781–787. 10.1111/j.1468-2982.2007.01343.xPubMedGoogle Scholar
- Unalp A, Dirik E, Kurul S: Prevalence and characteristics of recurrent headaches in Turkish adolescents. Pediatr Neurol 2006, 34: 110–115. 10.1016/j.pediatrneurol.2005.08.001PubMedGoogle Scholar
- Pothmann R, Frankenberg SV, Muller B, Sartory G, Hellmeier W: Epidemiology of headache in children and adolescents: evidence of high prevalence of migraine. Int J Behav Med 1994, 1: 76–89. 10.1207/s15327558ijbm0101_5PubMedGoogle Scholar
- Milovanovic M, Jarebinski M, Martinovic Z: Prevalence of primary headaches in children from Belgrade, Serbia. Eur J Paediatr Neurol 2007, 11: 136–141. 10.1016/j.ejpn.2006.11.010PubMedGoogle Scholar
- Karli N, Akis N, Zarifoglu M, Akgoz S, Irgil E, et al.: Headache prevalence in adolescents aged 12 to 17: a student-based epidemiological study in Bursa. Headache 2006, 46: 649–655. 10.1111/j.1526-4610.2006.00362.xPubMedGoogle Scholar
- Anttila P, Metsahonkala L, Sillanpaa M: Long-term trends in the incidence of headache in Finnish schoolchildren. Pediatrics 2006, 117: e1197-e1201. 10.1542/peds.2005-2274PubMedGoogle Scholar
- Ensink FB, Bautz M, Bruggenjurgen B, Hanekop GG: Prevalence of migraine in Germany. Schmerz 1994, 8: 155–161. 10.1007/BF02530392PubMedGoogle Scholar
- Rasmussen BK, Jensen R, Schroll M, Olesen J: Epidemiology of headache in a general population–a prevalence study. J Clin Epidemiol 1991, 44: 1147–1157. 10.1016/0895-4356(91)90147-2PubMedGoogle Scholar
- Lyngberg AC, Rasmussen BK, Jorgensen T, Jensen R: Has the prevalence of migraine and tension-type headache changed over a 12-year period? A Danish population survey. Eur J Epidemiol 2005, 20: 243–249. 10.1007/s10654-004-6519-2PubMedGoogle Scholar
- Classification Subcommittee of the International Headache Society: The international classification of headache disorders. 2nd Edition. Cephalalgia 2004, 24: 1–160.Google Scholar
- Headache Classification Committee of the International Headache Society: Classification and diagnostic criteria for headache disorders, cranial neuralgia and facial pain. Cephalalgia 1988, 8: 1–96. 10.1046/j.1468-2982.1988.0801001.xGoogle Scholar
- Lanteri-Minet M, Valade D, Geraud G, Chautard MH, Lucas C: Migraine and probable migraine–results of FRAMIG 3, a French nationwide survey carried out according to the 2004 IHS classification. Cephalalgia 2005, 25: 1146–1158. 10.1111/j.1468-2982.2005.00977.xPubMedGoogle Scholar
- Silberstein S, Loder E, Diamond S, Reed ML, Bigal ME, et al.: Probable migraine in the United States: results of the American Migraine Prevalence and Prevention (AMPP) study. Cephalalgia 2007, 27: 220–234. 10.1111/j.1468-2982.2006.01275.xPubMedGoogle Scholar
- Patel NV, Bigal ME, Kolodner KB, Leotta C, Lafata JE, et al.: Prevalence and impact of migraine and probable migraine in a health plan. Neurology 2004, 63: 1432–1438. 10.1212/01.WNL.0000142044.22226.54PubMedGoogle Scholar
- Katsarava Z, Dzagnidze A, Kukava M, Mirvelashvili E, Djibuti M, et al.: Primary headache disorders in the Republic of Georgia: prevalence and risk factors. Neurology 2009, 73: 1796–1803. 10.1212/WNL.0b013e3181c34abbPubMedGoogle Scholar
- Vucovic VP, Janculjak S, Ivankovic D, Plavec M, Lovrencic-Huzjan D, DemarinV A: Prevalence of migraine, probable migraine and tension-type headache in Croatian population. Cephalalgia 2007, 27: 647.Google Scholar
- Hagen K, Zwart JA, Vatten L, Stovner LJ, Bovim G: Head-HUNT: validity and reliability of a headache questionnaire in a large population-based study in Norway. Cephalalgia 2000, 20: 244–251. 10.1046/j.1468-2982.2000.00049.xPubMedGoogle Scholar
- Sillanpaa M, Anttila P: Increasing prevalence of headache in 7-year-old schoolchildren. Headache 1996, 36: 466–470. 10.1046/j.1526-4610.1996.3608466.xPubMedGoogle Scholar
- Honkasalo ML, Kaprio J, Heikkila K, Sillanpaa M, Koskenvuo M: A population-based survey of headache and migraine in 22,809 adults. Headache 1993, 33: 403–412. 10.1111/j.1526-4610.1993.hed3308403.xPubMedGoogle Scholar
- Swanson JW, Yanagihara T, Stang PE, O’Fallon WM, Beard CM, et al.: Incidence of cluster headaches: a population-based study in Olmsted County, Minnesota. Neurology 1994, 44: 433–437. 10.1212/WNL.44.3_Part_1.433PubMedGoogle Scholar
- Orji GI, Iloeje SO: Childhood migraine in Nigeria–I: a community-based study. West Afr J Med 1997, 16: 208–217.PubMedGoogle Scholar
- Zivadinov R, Willheim K, Jurjevic A, Sepic-Grahovac D, Bucuk M, et al.: Prevalence of migraine in Croatia: a population-based survey. Headache 2001, 41: 805–812. 10.1046/j.1526-4610.2001.01147.xPubMedGoogle Scholar
- Russell MB, Rasmussen BK, Thorvaldsen P, Olesen J: Prevalence and sex-ratio of the subtypes of migraine. Int J Epidemiol 1995, 15: 612–618.Google Scholar
- Boardman HF, Thomas E, Croft PR, Millson DS: Epidemiology of headache in an English district. Cephalalgia 2003, 23: 129–137. 10.1046/j.1468-2982.2003.00468.xPubMedGoogle Scholar
- Bandell-Hoekstra IE, Abu-Saad HH, Passchier J, Frederiks CM, Feron FJ, et al.: Prevalence and characteristics of headache in Dutch schoolchildren. Eur J Pain 2001, 5: 145–153. 10.1053/eujp.2001.0234PubMedGoogle Scholar
- Breslau N, Davis GC, Andreski P: Migraine, psychiatric disorders, and suicide attempts: an epidemiologic study of young adults. Psychiatry Res 1991, 37: 11–23. 10.1016/0165-1781(91)90102-UPubMedGoogle Scholar
- Carson AL, Rose KM, Sanford CP, Ephross SA, Stang PE, et al.: Lifetime prevalence of migraine and other headaches lasting 4 or more hours: the Atherosclerosis Risk in Communities (ARIC) study. Headache 2004, 44: 20–28. 10.1111/j.1526-4610.2004.04005.xPubMedGoogle Scholar
- Alders EE, Hentzen A, Tan CT: A community-based prevalence study on headache in Malaysia. Headache 1996, 36: 379–384. 10.1046/j.1526-4610.1996.3606379.xPubMedGoogle Scholar
- Deleu D, Khan MA, Al Shehab TA: Prevalence and clinical characteristics of headache in a rural community in oman. Headache 2002, 42: 963–973. 10.1046/j.1526-4610.2002.02225.xPubMedGoogle Scholar
- Lu SR, Fuh JL, Juang KD, Wang SJ: Migraine prevalence in adolescents aged 13–15: a student population-based study in Taiwan. Cephalalgia 2000, 20: 479–485. 10.1046/j.1468-2982.2000.00076.xPubMedGoogle Scholar
- Wang SJ, Liu HC, Fuh JL, Liu CY, Lin KP, et al.: Prevalence of headaches in a Chinese elderly population in Kinmen: age and gender effect and cross-cultural comparisons. Neurology 1997, 49: 195–200. 10.1212/WNL.49.1.195PubMedGoogle Scholar
- Bensenor IM, Lotufo PA, Goulart AC, Menezes PR, Scazufca M: The prevalence of headache among elderly in a low-income area of Sao Paulo, Brazil. Cephalalgia 2008, 28: 329–333. 10.1111/j.1468-2982.2007.01507.xPubMedGoogle Scholar
- Garcia-Pedroza F, Chandra V, Ziegler DK, Schoenberg B: Prevalence survey of headache in a rural Mexican village. Neuroepidemiology 1991, 10: 86–92. 10.1159/000110252PubMedGoogle Scholar
- Lavados PM, Tenhamm E: Epidemiology of migraine headache in Santiago, Chile: a prevalence study. Cephalalgia 1997, 17: 770–777. 10.1046/j.1468-2982.1997.1707770.xPubMedGoogle Scholar
- Mitchell P, Wang JJ, Currie J, Cumming RG, Smith W: Prevalence and vascular associations with migraine in older Australians. Aust N Z J Med 1998, 28: 627–632. 10.1111/j.1445-5994.1998.tb00659.xPubMedGoogle Scholar
- Osuntokun BO, Adeuja AO, Nottidge VA, Bademosi O, Alumide AO, et al.: Prevalence of headache and migrainous headache in Nigerian Africans: a community-based study. East Afr Med J 1992, 69: 196–199.PubMedGoogle Scholar
- Ho KH, Ong BK: A community-based study of headache diagnosis and prevalence in Singapore. Cephalalgia 2003, 23: 6–13. 10.1046/j.1468-2982.2003.00272.xPubMedGoogle Scholar
- Al Rajeh S, Bademosi O, Ismail H, Awada A, Dawodu A, et al.: A community survey of neurological disorders in Saudi Arabia: the Thugbah study. Neuroepidemiology 1993, 12: 164–178. 10.1159/000110316PubMedGoogle Scholar
- Mortimer MJ, Kay J, Gawkrodger DJ, Jaron A, Barker DC: The prevalence of headache and migraine in atopic children: an epidemiological study in general practice. Headache 1993, 33: 427–431. 10.1111/j.1526-4610.1993.hed3308427.xPubMedGoogle Scholar
- Antonov K, Isacson D: Headache and analgesic use in Sweden. Headache 1998, 38: 97–104. 10.1046/j.1526-4610.1998.3802097.xPubMedGoogle Scholar
- Bugdayci R, Ozge A, Sasmaz T, Kurt AO, Kaleagasi H, et al.: Prevalence and factors affecting headache in Turkish schoolchildren. Pediatr Int 2005, 47: 316–322. 10.1111/j.1442-200x.2005.02051.xPubMedGoogle Scholar
- Henry P, Auray JP, Gaudin AF, Dartigues JF, Duru G, et al.: Prevalence and clinical characteristics of migraine in France. Neurology 2002, 59: 232–237. 10.1212/WNL.59.2.232PubMedGoogle Scholar
- Lanteri-Minet M, Auray JP, El Hasnaoui A, Dartigues JF, Duru G, et al.: Prevalence and description of chronic daily headache in the general population in France. Pain 2003, 102: 143–149. 10.1016/s0304-3959(02)00348-2PubMedGoogle Scholar
- Sillanpaa M, Piekkala P, Kero P: Prevalence of headache at preschool age in an unselected child population. Cephalalgia 1991, 11: 239–242. 10.1046/j.1468-2982.1991.1105239.xPubMedGoogle Scholar
- Kristjansdottir G: Prevalence of pain combinations and overall pain: a study of headache, stomach pain and back pain among school-children. Scand J Soc Med 1997, 25: 58–63.PubMedGoogle Scholar
- Jousilahti P, Tuomilehto J, Rastenyte D, Vartiainen E: Headache and the risk of stroke: a prospective observational cohort study among 35,056 Finnish men and women. Arch Intern Med 2003, 163: 1058–1062. 10.1001/archinte.163.9.1058PubMedGoogle Scholar
- Bille B: Migraine in school children. A study of the incidence and short-term prognosis, and a clinical, psychological and electroencephalographic comparison between children with migraine and matched controls. Acta Paediatr 1962, 51: 1–151.Google Scholar
- Dyb G, Holmen TL, Zwart JA: Analgesic overuse among adolescents with headache: the Head-HUNT-Youth Study. Neurology 2006, 66: 198–201. 10.1212/01.wnl.0000193630.03650.19PubMedGoogle Scholar
- Martin S: Prevalence of migraine headache in Canada. CMAJ 2001, 164: 1481.PubMed CentralPubMedGoogle Scholar
- Wong TW, Wong KS, Yu TS, Kay R: Prevalence of migraine and other headaches in Hong Kong. Neuroepidemiology 1995, 14: 82–91. 10.1159/000109782PubMedGoogle Scholar
- Shivpuri D, Rajesh MS, Jain D: Prevalence and characteristics of migraine among adolescents: a questionnaire survey. Indian Pediatr 2003, 40: 665–669.PubMedGoogle Scholar
- Yoon MS, Obermann M, Fritsche G, Slomke M, Dommes P, et al.: Population-based validation of a German-language self-administered headache questionnaire. Cephalalgia 2008, 28: 605–608. 10.1111/j.1468-2982.2008.01560.xPubMedGoogle Scholar
- Hagen K, Zwart JA, Aamodt AH, Nilsen KB, Brathen G, et al.: The validity of questionnaire-based diagnoses: the third Nord-Trondelag Health Study 2006–2008. J Headache Pain 2010, 11: 67–73. 10.1007/s10194-009-0174-7PubMed CentralPubMedGoogle Scholar
- Andrée C, Vaillant M, Barré J, Katsarava Z, Lainez JM, et al.: Development and validation of the EUROLIGHT questionnaire to evaluate the burden of primary headache disorders in Europe. Cephalalgia 2010, 30: 1082–1100. 10.1177/0333102409354323PubMedGoogle Scholar
- Stewart WF, Lipton RB, Kolodner KB, Sawyer J, Lee C, et al.: Validity of the Migraine Disability Assessment (MIDAS) score in comparison to a diary-based measure in a population sample of migraine sufferers. Pain 2000, 88: 41–52. 10.1016/S0304-3959(00)00305-5PubMedGoogle Scholar
- Lipton RB, Bigal ME, Kolodner K, Stewart WF, Liberman JN, et al.: The family impact of migraine: population-based studies in the USA and UK. Cephalalgia 2003, 23: 429–440. 10.1046/j.1468-2982.2003.00543.xPubMedGoogle Scholar
- Pradalier A, Auray JP, El Hasnaoui A, Alzahouri K, Dartigues JF, et al.: Economic impact of migraine and other episodic headaches in France: data from the GRIM2000 study. Pharmacoeconomics 2004, 22: 985–999. 10.2165/00019053-200422150-00003PubMedGoogle Scholar
- Hu XH, Markson LE, Lipton RB, Stewart WF, Berger ML: Burden of migraine in the United States: disability and economic costs. Arch Intern Med 1999, 159: 813–818. 10.1001/archinte.159.8.813PubMedGoogle Scholar
- Berg J, Stovner LJ: Cost of migraine and other headaches in Europe. Eur J Neurol 2005,12(Suppl 1):59–62.PubMedGoogle Scholar
- Olson SH, Kelsey JL, Pearson TA, Levin B: Evaluation of random digit dialing as a method of control selection in case-control studies. Am J Epidemiol 1992, 135: 210–222.PubMedGoogle Scholar
- Linde M, Dahlöf C: Attitudes and burden of disease among self-considered migraineurs–a nation-wide population-based survey in Sweden. Cephalalgia 2004, 24: 455–465. 10.1111/j.1468-2982.2004.00703.xPubMedGoogle Scholar
- Vandenbroucke JP, Von Elm E, Altman DG, Gotzsche PC, Mulrow CD, et al.: Strengthening the Reporting of Observational Studies in Epidemiology (STROBE): explanation and elaboration. Epidemiology 2007, 18: 805–835. 10.1097/EDE.0b013e3181577511PubMedGoogle Scholar
- World Health Organization and Lifting The Burden: Atlas of headache disorders and resources in the world 2011. Geneva: World Health Organization; 2011.Google Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.