The epidemiology of primary headache disorders in Zambia: a population-based door-to-door survey

Abstract

BackgroundLittle is known of the epidemiology of primary headache disorders in sub-Saharan Africa. We performed a population-based survey in Zambia using methods previously tested in multiple other countries.MethodsThis cross-sectional survey was conducted by visiting households unannounced, using cluster-randomized sampling, in the mostly urban Lusaka Province and mostly rural Southern Province. Within clusters, households were selected randomly, as was one adult member (18-65 years old) of each selected household. A structured questionnaire, translated into the local languages, was administered face-to-face by trained interviewers. Demographic enquiry was followed by diagnostic questions based on ICHD-II criteria. A random sub-sample of participants were invited for subsequent physician-interview to validate the diagnostic part of the questionnaire.ResultsOf 1,134 eligible household members contacted, 1,085 (450 male, 887 urban) consented to interview (refusal rate 4.3%). Others who had been selected but remained unavailable on three visits were not counted as refusals since their reasons were unknown, but gave rise to gender biases, being mostly male in urban areas and mostly female in rural areas. Statistical correction was applied. Adjusted for gender and habitation (urban/rural), the 1-year prevalence of any headache was 61.6%, of migraine 22.9%, of tension-type headache (TTH) 22.8%, of headache on ≥15 days/month 11.5% and of probable medication-overuse headache (pMOH) 7.1%. The adjusted point-prevalence of any headache (headache yesterday) was 19.1%. There was a small proportion (5.3%) of unclassified headache, some of which may have been secondary. The overwhelmingly strong association was between urban dwelling and pMOH (OR: 8.6; P=0.0001), with an urban prevalence of 14.5% (gender-adjusted). Validation of the questionnaire was limited by participants’ reluctance to present for physician review, substantial delays in doing so and major self-selection bias among those who did. These were unavoidable problems in resource-limited Zambia.ConclusionsPrimary headache disorders, common in high-income countries, are at least as prevalent in Zambia, a sub-Saharan African country. The selectively urban problem of pMOH seems likely to reflect ready availability of non-prescription analgesics, without easy access to professional health care for headache or any focused public-health education regarding correct usage of analgesics or the dangers of their overuse.

The challenge of managing headache disorders in a tertiary referral neurology clinic in Rwanda

“…This result is consistent with what has been recently reported from Zambia: 7.1% (1-year prevalence) 19. This similarity is curious since these 2 studies have different methodological approaches: population-based versus single-centered.…”

Prevalence and incidence of neurological disorders among adult Ugandans in rural and urban Mukono district; a cross-sectional study

“…A higher prevalence was recorded in Zambia (72%) (gender- and habitation-adjusted 61.6%) [34] whereas, lower prevalence was reported in Ethiopia (21.6%) [35] and Tanzania (23.1%) [36]. The differences in the prevalence could be attributed to different methodologies used, as well as cultural and population characteristics of the studied patients.…”

The prevalence of primary headache disorders in Ethiopia

“…This was the second such study within the Global Campaign against Headache to be conducted in SSA: the first was in Zambia, and showed not dissimilar overall results with regard to both migraine (gender- and habitation-adjusted 1-year prevalence 22.9%) and TTH (22.8%) [17]. TTH was the most prevalent headache in Ethiopia, but only by a small margin, and not so in Zambia [17]; we speculate that this may have been due to cultural under-reporting of infrequent episodic TTH in both countries.…”

“…The few studies of headache prevalence, including one in Ethiopian textile mill workers [7], have mostly been in select sub-populations rather than population-based [7–15], with estimates varying considerably but generally far lower than global means [16]. The consequent perception that headache disorders were relatively uncommon in SSA, and not of significant public-health concern, was reversed after the completion of a survey in Zambia [17, 18]. This study, supported by Lifting The Burden (LTB), a UK-registered non-governmental organization conducting the Global Campaign in official relations with the World Health Organization (WHO) [19], reported highly prevalent migraine (22.9%), TTH (22.8%) and probable medication-overuse headache (pMOH) (7.1%) [17].…”

“…The consequent perception that headache disorders were relatively uncommon in SSA, and not of significant public-health concern, was reversed after the completion of a survey in Zambia [17, 18]. This study, supported by Lifting The Burden (LTB), a UK-registered non-governmental organization conducting the Global Campaign in official relations with the World Health Organization (WHO) [19], reported highly prevalent migraine (22.9%), TTH (22.8%) and probable medication-overuse headache (pMOH) (7.1%) [17]. These were associated with heavy disability burden and lost productivity, calling for action and recognition within public health policy [18].…”