Regional and Sex Differences in the Prevalence and Awareness Of
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j ORIGINAL RESEARCH gSCIENCE Regional and Sex Differences in the Prevalence and Awareness of Hypertension The authors report no An H3Africa AWI-Gen Study Across 6 Sites in Sub-Saharan Africa relationships that could be construed as a conflict of F. Xavier Gómez-Olivé*,y,z, Stuart A. Alix, Felix Madex, Catherine Kyobutungik, Engelbert Nonterah{, interest. fi # yy x,zz { This paper describes the Lisa Mickles eld , Marianne Alberts**, Romuald Boua , Scott Hazelhurst , Cornelius Debpuur , views of the authors and yy xx k x Felistas Mashinya**, Sekgothe Dikotope**, Hermann Sorgho , Ian Cook , Stella Muthuri , Cassandra Soo , does not necessarily Freedom Mukomanax, Godfred Agongo{, Christopher Wandabwak, Sulaimon Afolabi*, Abraham Oduro{, represent the official views yy k # of the National Institutes of Halidou Tinto , Ryan G. Wagner*, Tilahun Haregu , Alisha Wade*, Kathleen Kahn*, Shane A. Norris , Health or the NRF. kk y,{{,## x, Nigel J. Crowther , Stephen Tollman*, Osman Sankoh , Michèle Ramsay *** : as members of AWI-Gen The AWI-Gen Collaborative and the H3Africa Consortium Centre is funded by the National Institutes of Johannesburg, South Africa; Accra, Ghana; Cambridge, MA, USA; Nairobi, Kenya; Navrongo, Ghana; Health (Grant No. Polokwane, South Africa; Nanoro, Burkina Faso; and Njala, Sierra Leone 1U54HG006938) as part of the H3Africa Consortium. Michèle Ramsay is a South ABSTRACT African Research Chair in Genomics and Background: Bioinformatics of African There is a high prevalence of hypertension and related cardiovascular diseases in sub-Saharan Populations hosted by the Africa, yet few large studies exploring hypertension in Africa are available. The actual burden of disease is University of the poorly understood and awareness and treatment to control it is often suboptimal. Witwatersrand, funded by the Department of Science Objectives: The study sought to report the prevalence of measured hypertension and to assess awareness and Technology and administered by National and control of blood pressure among older adults in rural and urban settings in 6 sites located in West, Research Foundation of East, and Southern Africa. In addition, we examined regional, sex, and age differences related to South Africa (NRF). Osman hypertension. Sankoh is Executive Director of INDEPTH. The Methods: A population-based cross-sectional study was performed at 6 sites in 4 African countries: Burkina INDEPTH Network receives core support funding from Faso (Nanoro), Ghana (Navrongo), Kenya (Nairobi), and South Africa (Agincourt, Dikgale, Soweto). Blood the William and Flora pressure measurements were taken using standardized procedures on 10,696 adults 40 to 60 years of age. Hewlett Foundation, Hypertension was defined as systolic blood pressure 140 mm Hg or diastolic blood pressure 90 mm Hg or Sida/Research Cooperation and Wellcome Trust. The taking antihypertensive medication. Agincourt HDSS received Results: core support from the The mean prevalence of hypertension ranged from 15.1% in Nanoro to 54.1% in Soweto. All 3 of the University of the South African sites had a mean prevalence of hypertension of over 40.0%, significantly higher than in Nairobi Witwatersrand and the (25.6%) and Navrongo (24.5%). Prevalence increased with age in both sexes and at all sites. A significantly Medical Research Council, South Africa, and the higher prevalence of hypertension was observed in women in Agincourt, Dikgale, and Nairobi, whereas in Wellcome Trust, UK (Grants Nanoro this trend was reversed. Within the hypertensive group the average proportion of participants who 058893/Z/99/A; 069683/Z/ were aware of their blood pressure status was only 39.4% for men and 53.8% for women, and varied 02/Z; 085477/Z/08/Z; 085477/B/08/Z). The widely across sites. Nairobi HDSS receives core Conclusions: support from Sida and the Our study demonstrates that the prevalence of hypertension and the level of disease awareness William and Flora Hewlett differ not only between but also within sub-Saharan African countries. Each nation must tailor their Foundation. The Soweto regional hypertension awareness and screening programs to match the characteristics of their local Cohort (DPHRU) is supported by the Univer- populations. sity of the Witwatersrand, the Medical Research Hypertension is a rising global health problem, with an death in this region, with a high prevalence of hypertension Council, South Africa, estimated 1 billion people living with hypertension, and found in many SSA settings. The WHO-SAGE (World DST-NRF Centre for Excellence in Human 9.4 million related annual deaths worldwide [1,2]. Low- Health Organization Study on Global Ageing and Adult Development, and The and middle-income countries suffer two-thirds of the Health) study [6], which compared nationally representa- Wellcome Trust. The global burden of cardiovascular disease (CVD), which is tive populations over 50 years of age from China, Russia, Dikgale HDSS has received associated with inadequate treatment of hypertension [3]. India, Ghana, South Africa, and Mexico, reported that the funding from the Norwe- gian Universities Commit- In sub-Saharan Africa (SSA) hypertension has become a prevalence of hypertension in South Africa was among the tee for Development major public health problem [4,5]. At present, CVDs are highest at over 77%. At the same time, the study reported Research and Education considered to be a significant contributor to premature low levels of awareness and blood pressure control in all of (NUFU); the Free University GLOBAL HEART, VOL. 12, NO. 2, 2017 81 June 2017: 81-90 j gSCIENCE of Amsterdam; the these countries [6]. In the absence of an effective inter- Informed consent, and anonymization of INDEPTH Network; the vention strategy to control this epidemic, it is expected that Flemish Inter-University participant identity Council (VLIR), Belgium; hypertension-associated CVD will continue to rise, with a All participants provided written informed consent before the National Research concomitant increase in mortality and disability [7,8]. any study procedures were conducted. Each participant Foundation, South Africa; Despite global concerns over hypertension, there was assigned a random AWI-Gen study participant identity and the University of seems to be a dearth of information for most African code, which was used on study documentation, and the Limpopo. countries on its prevalence, the levels of awareness by in- From the *MRC/Wits Rural key linking participant identity and their identity code Public Health and Health dividuals on their blood pressure status, and how effective locked securely away at the research site, and not entered Transitions Research Unit treatment is [9]. This is especially so in the population onto any further study documentation. (Agincourt), School of age group of 40 to 60 years of age, which is the age at Public Health, Faculty of which individuals suffer the highest levels of blood Health Sciences, University e of the Witwatersrand, pressure related disease [10,11]. Measurement of blood pressure Johannesburg, South The principal aims of the current study were therefore Blood pressure was measured using a sphygmomanometer y Africa; INDEPTH Network, to measure the prevalence, level of awareness, and control (Omron M6, Omron, Kyoto, Japan), according to the Accra, Ghana; zHarvard of hypertension in a large population of 40- to 60-year-old following standardized procedure: participants were seated Center for Population and participants of both sexes in 6 research sites across 4 SSA Development Studies, upright in a chair, with feet resting firmly on the floor and Harvard T.H. Chan School countries. not crossed. To ensure that the antecubital fossa was at the of Public Health, Harvard level of the heart participants were seated with the left arm University, Cambridge, MA, METHODS USA; xSydney Brenner resting on a desk or arm rest. The cuff was placed on the Institute for Molecular This study draws on the Africa Wits-INDEPTH (University arm about 2 to 3 cm above the antecubital fossa, and not Bioscience, Faculty of of the Witwatersrand, Johannesburg, and the International restricted by clothing. The participant was allowed to relax Health Sciences, University Network for the Demographic Evaluation of Populations for 3 to 5 min before blood pressure was measured. Three of the Witwatersrand, and Their Health) [12] partnership for Genomic Studies measurements were taken, at 2-min intervals. During this Johannesburg, South k (AWI-Gen), which is a National Institutes of Health- period, participants remained quiet and still. The mean of Africa; African Population e and Health Research funded Collaborative Centre of the Human Heredity and the last 2 measurements was used to calculate the final Center, Nairobi, Kenya; Health in Africa (H3Africa) Consortium [13,14]. The pri- systolic blood pressure and diastolic blood pressure. {Navrongo Health mary aim of AWI-Gen is to study genetic and environ- Research Centre, mental factors that contribute to cardiometabolic disease in Navrongo, Ghana; #MRC/ Wits Developmental African populations. Six study sites in 4 SSA countries are Diagnosis of hypertension Pathways for Health involved in AWI-Gen: in South Africa the MRC/Wits Blood pressure measurements were classified according to Research Unit, Faculty of Agincourt Health and Demographic Surveillance System the JNC7 guidelines of the Joint National Committee of Health Sciences, University Site (HDSS) [15], Dikgale HDSS [16], and the Soweto of the Witwatersrand, Prevention, Detection,