Prevalence and sociodemographic correlates of primary headache disorders: results of a population-based survey from Bangalore, India.

BACKGROUND: Headache disorders are common and burdensome throughout the world, placing high demand on health care services. Good information on their prevalence and distribution through sectors of the population are a prerequisite for planning interventions and organizing services, but unavailable for India. OBJECTIVES: To find out the prevalence of headache disorders in Karnataka State and establish important sociodemographic associations. MATERIALS AND METHODS: Using a door to door survey technique, amongst 2997 households, 2329 individuals were interviewed with a validated structured questionnaire by randomly sampling one adult member (aged 18-65 years) from eligible households in urban (n = 1226) and rural (n = 1103) areas of Bangalore, during the period April 2009 and January 2010. STATISTICAL ANALYSIS USED: Chi-square, odds ratio (OR), and logistic regression. RESULTS: The 1-year prevalence of headache was 63.9% (62.0% when adjusted for age, gender and habitation) and 1-day prevalence (headache on the day prior to the survey) was 5.9%. Prevalence was higher in the age groups of 18-45 years, among females (OR = 2.3; 95% confidence interval: 1.9-2.7) and those in rural areas. Prevalence was higher in rural (71.2 [68.4-73.8]) than in urban areas (57.3 [54.5-60.1]) even after adjusting for gender. The proportion of days lost to headache from paid work was 1.1%, while overall productivity loss (from both paid and household work) was 2.8%. CONCLUSIONS: Headache disorders are a major health problem in India with significant burden. It requires systematic efforts to organize effective services to be able to reach a large number of people in urban and rural India. Education of physicians and other health-care workers, and the public should be a pillar of such efforts.

The methodology of population surveys of headache prevalence, burden and cost: principles and recommendations from the Global Campaign against Headache.

The global burden of headache is very large, but knowledge of it is far from complete and needs still to be gathered. Published population-based studies have used variable methodology, which has influenced findings and made comparisons difficult. Among the initiatives of the Global Campaign against Headache to improve and standardize methods in use for cross-sectional studies, the most important is the production of consensus-based methodological guidelines. This report describes the development of detailed principles and recommendations. For this purpose we brought together an expert consensus group to include experience and competence in headache epidemiology and/or epidemiology in general and drawn from all six WHO world regions. The recommendations presented are for anyone, of whatever background, with interests in designing, performing, understanding or assessing studies that measure or describe the burden of headache in populations. While aimed principally at researchers whose main interests are in the field of headache, they should also be useful, at least in parts, to those who are expert in public health or epidemiology and wish to extend their interest into the field of headache disorders. Most of all, these recommendations seek to encourage collaborations between specialists in headache disorders and epidemiologists. The focus is on migraine, tension-type headache and medication-overuse headache, but they are not intended to be exclusive to these. The burdens arising from secondary headaches are, in the majority of cases, more correctly attributed to the underlying disorders. Nevertheless, the principles outlined here are relevant for epidemiological studies on secondary headaches, provided that adequate definitions can be not only given but also applied in questionnaires or other survey instruments.

Diagnosis, prevalence estimation and burden measurement in population surveys of headache: presenting the HARDSHIP questionnaire.

The global burden of headache is very large, but knowledge of it is far from complete and needs still to be gathered. Published population-based studies have used variable methodology, which has influenced findings and made comparisons difficult. The Global Campaign against Headache is undertaking initiatives to improve and standardize methods in use for cross-sectional studies. One requirement is for a survey instrument with proven cross-cultural validity. This report describes the development of such an instrument. Two of the authors developed the initial version, which was used with adaptations in population-based studies in China, Ethiopia, India, Nepal, Pakistan, Russia, Saudi Arabia, Zambia and 10 countries in the European Union. The resultant evolution of this instrument was reviewed by an expert consensus group drawn from all world regions. The final output was the Headache-Attributed Restriction, Disability, Social Handicap and Impaired Participation (HARDSHIP) questionnaire, designed for application by trained lay interviewers. HARDSHIP is a modular instrument incorporating demographic enquiry, diagnostic questions based on ICHD-3 beta criteria, and enquiries into each of the following as components of headache-attributed burden: symptom burden; health-care utilization; disability and productive time losses; impact on education, career and earnings; perception of control; interictal burden; overall individual burden; effects on relationships and family dynamics; effects on others, including household partner and children; quality of life; wellbeing; obesity as a comorbidity. HARDSHIP already has demonstrated validity and acceptability in multiple languages and cultures. Modules may be included or not, and others (e.g., on additional comorbidities) added, according to the purpose of the study and resources (especially time) available.

Improving quality in population surveys of headache prevalence, burden and cost: key methodological considerations.

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.