title: Hypertension in sub-Saharan Africa: cross-sectional surveys in four rural and urban communities.
abstract: BACKGROUND
  Cardiovascular disease (CVD) is the leading cause of adult mortality in low-income countries but data on the prevalence of cardiovascular risk factors such as hypertension are scarce, especially in sub-Saharan Africa (SSA). This study aims to assess the prevalence of hypertension and determinants of blood pressure in four SSA populations in rural Nigeria and Kenya, and urban Namibia and Tanzania.
  
  
  RESULTS
  We performed four cross-sectional household surveys in Kwara State, Nigeria; Nandi district, Kenya; Dar es Salaam, Tanzania and Greater Windhoek, Namibia, between 2009-2011. Representative population-based samples were drawn in Nigeria and Namibia. The Kenya and Tanzania study populations consisted of specific target groups. Within a final sample size of 5,500 households, 9,857 non-pregnant adults were eligible for analysis on hypertension. Of those, 7,568 respondents ≥ 18 years were included. The primary outcome measure was the prevalence of hypertension in each of the populations under study. The age-standardized prevalence of hypertension was 19.3% (95%CI:17.3-21.3) in rural Nigeria, 21.4% (19.8-23.0) in rural Kenya, 23.7% (21.3-26.2) in urban Tanzania, and 38.0% (35.9-40.1) in urban Namibia. In individuals with hypertension, the proportion of grade 2 (≥ 160/100 mmHg) or grade 3 hypertension (≥ 180/110 mmHg) ranged from 29.2% (Namibia) to 43.3% (Nigeria). Control of hypertension ranged from 2.6% in Kenya to 17.8% in Namibia. Obesity prevalence (BMI ≥ 30) ranged from 6.1% (Nigeria) to 17.4% (Tanzania) and together with age and gender, BMI independently predicted blood pressure level in all study populations. Diabetes prevalence ranged from 2.1% (Namibia) to 3.7% (Tanzania).
  
  
  CONCLUSIONS
  Hypertension was the most frequently observed risk factor for CVD in both urban and rural communities in SSA and will contribute to the growing burden of CVD in SSA. Low levels of control of hypertension are alarming. Strengthening of health care systems in SSA to contain the emerging epidemic of CVD is urgently needed.
authors.affiliation: Department of Global Health, Academic Medical Center, University of Amsterdam, Amsterdam Institute for Global Health and Development, Amsterdam, The Netherlands. m.hendriks@aighd.org
authors.forename: Marleen E
authors.initials: ME
authors.lastname: Hendriks
authors.forename: Ferdinand W N M
authors.initials: FW
authors.lastname: Wit
authors.forename: Marijke T L
authors.initials: MT
authors.lastname: Roos
authors.forename: Lizzy M
authors.initials: LM
authors.lastname: Brewster
authors.forename: Tanimola M
authors.initials: TM
authors.lastname: Akande
authors.forename: Ingrid H
authors.initials: IH
authors.lastname: de Beer
authors.forename: Sayoki G
authors.initials: SG
authors.lastname: Mfinanga
authors.forename: Amos M
authors.initials: AM
authors.lastname: Kahwa
authors.forename: Peter
authors.initials: P
authors.lastname: Gatongi
authors.forename: Gert
authors.initials: G
authors.lastname: Van Rooy
authors.forename: Wendy
authors.initials: W
authors.lastname: Janssens
authors.forename: Judith
authors.initials: J
authors.lastname: Lammers
authors.forename: Berber
authors.initials: B
authors.lastname: Kramer
authors.forename: Igna
authors.initials: I
authors.lastname: Bonfrer
authors.forename: Esegiel
authors.initials: E
authors.lastname: Gaeb
authors.forename: Jacques
authors.initials: J
authors.lastname: van der Gaag
authors.forename: Tobias F
authors.initials: TF
authors.lastname: Rinke de Wit
authors.forename: Joep M A
authors.initials: JM
authors.lastname: Lange
authors.forename: Constance
authors.initials: C
authors.lastname: Schultsz
mesh_terms: D000328:Adult; D017954:Africa South of the Sahara / Q000453:epidemiology; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000209:etiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012423:Rural Health / Q000706:statistics & numerical data*; D012737:Sex Factors; D014504:Urban Health / Q000706:statistics & numerical data*