Final Full P Paper Theme 9: Health, Mortality and Longevity - PDF document

Final Full P Paper Theme 9: Health, Mortality and Longevity Prevalence ce a and d dete terminants ts o of h hyperte tension in in Namibia - a n nati tional l level cr cross-secti tional s stu tudy Craig, LS 1,2 , Gage, AJ 1,3 1 Tulane University School of Public Health and Tropical Medicine; 2 lcraig1@tulane.edu; 3 agage@tulane.edu Abstr tract ct Ba Backgr ground: : Globally, an estimated 28 million people die from non-communicable diseases (NCDs) such as cardiovascular disease, cancer, chronic respiratory disease and diabetes every year. By 2030, it is projected that NCDs will become the leading cause of death in sub-Saharan Africa. In Namibia, the emergent NCD epidemic is largely driven by hypertension, with evidence indicating remarkably high prevalence among urban residents. This study estimates the prevalence and determinants of hypertension among Namibian adults. Meth thods: : The analysis is based on 2,537 women and 2,163 men aged 35-64 years from the nationally- representative 2013 Namibia Demographic and Health Survey. Odds radios and 95% confidence intervals were estimated using logistic regression. Results ts: : The prevalence of hypertension was 32.8% (men: 30.2%; women: 34.9%; p=0.0059). Older age, urban residence, and being obese were positively associated with the odds of hypertension (p<0.05). For women, the odds of hypertension were significantly increased for those who were diabetic and reduced for those with higher levels of education. Co Concl clusion: : The prevalence of hypertension is high and associated with metabolic and socio-demographic factors among Namibian adults. Future research examining disease comorbidity and behavioral risk factors could better inform on the disease burden and help target resources to optimize prevention and control. Leslie Craig & Anastasia Gage, Tulane University School of Public Health & Tropical Medicine Topic 910: Non-communicable diseases & their related risk factors in developing countries

Final Full P Paper Theme 9: Health, Mortality and Longevity Ba Backgr ground In recent years, non-communicable diseases (NCDs) such as cardiovascular diseases, diabetes, cancer and chronic respiratory diseases have emerged as a major threat to global economies and health systems, as well as individual health and well-being. 1 – 4 The current death and disability burden from NCDs disproportionately affects low- and middle-income countries (LMICs) and is projected to increase substantially over the next two decades with a near tripling of disease mortality in Latin America and the Caribbean, the Middle East, and sub-Saharan Africa (SSA). 2 – 7 This threat is especially concerning for resource-constrained regions, including those countries in SSA, which must now contend with a double burden in disease and mortality from communicable diseases and NCDs. 4 In SSA, the NCD epidemic is largely driven by hypertension, 2,8,9 with evidence from a 2017 pooled analysis of worldwide trends in blood pressure showing that the highest levels of blood pressure worldwide have shifted from high-income countries to low income countries in South Asia and SSA. 10 Data from these pooled analyses suggest that both mean systolic and diastolic blood pressures have increased among men and women in SSA – although estimated trends in this region are noted to carry larger uncertainty due to use of small sample sizes or non-national samples. 10 In addition, a gender differential in the burden of disease has been identified, with a female excess in age-standardized mean systolic blood pressure and hypertension prevalence in SSA. 10 One 2012 cross-sectional study of hypertension across four rural and urban communities in SSA reported age-standardized prevalence estimates of 19.3% (95%CI:17.3 – 21.3), 21.4% (19.8 – 23.0), 23.7% (21.3 – 26.2) and 38.0% (35.9 – 40.1) in rural Nigeria, rural Kenya, urban Tanzania and urban Namibia, respectively. 6 These estimates support theories of the magnitude of the hypertension burden in SSA and provide shocking evidence of a remarkably high burden among urban Namibian residents (crude: 32%; age-standardized: 38%) which is similar to that of non-Hispanic black adults in the USA (38.6%). 9,11 Despite evidence of high disease prevalence in urban Namibia, few studies have addressed the national burden of NCDs while, to the best of my knowledge, no research has yet been directed towards the social aspects of these diseases. Consistent global information has been described as imperative to inform on the national burden of NCDs, improve understanding of blood pressure levels and trends, identify vulnerable populations, and guide the design and implementation of needed interventions. 10 Accordingly, among the nine global NCD targets, endorsed by the World Health Assembly in 2013, is to lower the prevalence of raised blood pressure, by 25% by 2025. 3,10 Nationally representative data from the 2013 Namibia Demographic and Health Survey (NDHS) are now available, and include physical and biochemical measurements of common NCD biomarkers (e.g. blood pressure, fasting blood glucose, body mass index) among a subsample of women and men, 35-64 years of age. This study aims to estimate the prevalence of hypertension among Namibian adults 35-64 years of age, and the associations with select socio-demographic, metabolic and behavioural determinants, in order to - 1- Leslie Craig & Anastasia Gage, Tulane University School of Public Health & Tropical Medicine Topic 910: Non-communicable diseases & their related risk factors in developing countries

Final Full P Paper Theme 9: Health, Mortality and Longevity provide baseline data on the hypertension burden in country and inform the targeting of interventions to improve overall management and prevention of these diseases. Meth thods This study used data from the 2013 NDHS, the fourth comprehensive, national-level population and health survey conducted in Namibia as part of the global DHS programme. 12 Namibia, one of the least densely populated countries in the world, is a middle-income country in SSA with a population just over 2 million. 12 The country is divided into 3 main regions – north, central and south – and, despite rapid urbanization, remains largely rural. 12 The 2013 NDHS used a nationally-representative two-stage stratified cluster design and represents the first national survey in Namibia to include biomarker measurements of blood pressure and fasting blood glucose. 12 Biomarker measurements were performed in half of the survey households, using guidelines that were largely consistent with the World Health Organization (WHO) “STEPwise approach to the surveillance of non- communicable diseases” (STEPS) methodology. 12,13 Details of the survey design, sampling procedures and data collection methods are provided in the country report. 12 Following the exclusion of pregnant women, the study sample included 2,537 eligible women and 2,163 eligible men, 35-64 years of age. Variables The primary outcome in this study was hypertension prevalence, which was defined, according to WHO criteria as systolic blood pressure (SBP) of 140 mmHg or greater, diastolic blood pressure (DBP) of 90 mmHg or greater, and/or currently taking antihypertensive medications. 2 Additional analyses also explored variation in secondary outcomes of hypertension awareness, treatment and control by socio- demographic characteristics. Awareness of hypertension was defined according to self-report of previous diagnosis of high blood pressure (hypertension) by a doctor or other health worker. Treatment of hypertension was defined as self-reported use of prescribed medication to control blood pressure. Control of hypertension was defined as pharmacologic treatment of hypertension associated with an average SBP <140 mm Hg and an average DBP <90 mm Hg. Independent variables were coded categorically and included the sex of the respondent (male or female), age-group (35 – 39, 40 – 44, 45 – 49, 50 – 54, 55 – 59 or 60 – 64 years), highest level of education (no education or preschool only, primary schooling, or secondary school or higher), place of residence (urban or rural), marital status (never married, currently married, or formerly/ever married), employment status (not currently working, or currently working), and quintiles of wealth. The NDHS 2013 did not explicitly allow for self-report of ethnicity so language of the respondent was used as a proxy (Oshiwambo, Damara/Nama, Afrikaans, Herero or other). Smoking was classified into three categories (do not currently smoke, smoke cigarettes, or smoke pipes, cigars, etc.). Body mass index (BMI) was classified based on WHO categories of underweight (less than 18.5 kg/m 2 ), normal weight (18.5 – 24.9 kg/m 2 ), overweight - 2- Leslie Craig & Anastasia Gage, Tulane University School of Public Health & Tropical Medicine Topic 910: Non-communicable diseases & their related risk factors in developing countries