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.
Methods and Findings: 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).
Conclusion: 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.
