Prevalence of hypertension and associated cardiovascular risk factors in an urban slum in Nairobi, Kenya: a population-based survey.

BACKGROUND: Urbanisation has been described as a key driver of the evolving non-communicable disease (NCD) epidemic. In Africa, hypertension is the commonest cardiovascular problem. We determined the prevalence and risk factor correlates of hypertension in the largest Nairobi slum. METHODS: In 2010 we conducted a population-based household survey in Kibera, a large informal settlement in Nairobi City; utilising cluster sampling with probability proportional to size. Households were selected using a random walk method. The WHO instrument for stepwise surveillance (STEPS) of chronic disease risk factors was administered by trained medical assistants, who also recorded blood pressure (BP) and anthropometric measures. BP was recorded using a mercury sphygmomanometer utilising the American Heart Association guidelines. Hypertension was defined as per the 7th Report of the Joint National Committee or use of prescribed antihypertensive medication. Those with hypertension or with random capillary blood sugar (RCBS) >11.1 mmol/l had an 8 hours fasting venous blood sugar sample drawn. Age standardised prevalence was computed and multivariate analysis to assess associations. RESULTS: We screened 2200 and enrolled 2061 adults; 50.9% were males; mean age was 33.4 years and 87% had primary level education. The age-standardised prevalence of hypertension (95% CI) was 22.8% (20.7, 24.9). 20% (53/258) were aware of their hypertensive status; 59.3% had pre-hypertension; 80% reported high levels of physical activity and 52% were classified as harmful alcohol drinkers; 10% were current smokers and 5% had diabetes. Majority of males had normal BMI and waist circumference, whereas a third of females were obese or overweight and 40% had central obesity. Older age, higher general and central obesity were independently associated with hypertension and higher SBP and DBP readings. CONCLUSIONS: Our findings of high prevalence of hypertension, in association with excess body weight in this poor urban slum community, point to the need for greater awareness and implementation of primary preventive strategies.

A population-based survey of prevalence of diabetes and correlates in an urban slum community in Nairobi, Kenya.

BACKGROUND: Urban slum populations in Africa continue to grow faster than national populations. Health strategies that focus on non-communicable diseases (NCD) in this segment of the population are generally lacking. We determined the prevalence of diabetes and associated cardiovascular disease (CVD) risk factors correlates in Kibera, Nairobi's largest slum. METHODS: We conducted a population-based household survey utilising cluster sampling with probability proportional to size. Households were selected using a random walk method and consenting residents aged 18 years and above were recruited. The WHO STEPS instrument was administered. A random capillary blood sugar (RCBS) was obtained; known persons with diabetes and subjects with a RCBS >11.1 had an 8 hours fasting blood sugar (FBS) drawn. Diabetes was defined as a RCBS of ≥ 11.1 mmol/l and a FBS of ≥ 7.0 mmol/l, or a prior diagnosis or receiving diabetes drug treatment. RESULTS: Out of 2061 enrolled; 50.9% were males, mean age was 33.4 years and 87% had a minimum of primary education. Only 10.6% had ever had a blood sugar measurement. Age adjusted prevalence of diabetes was 5.3% (95% CI 4.2-6.4) and prevalence increased with age peaking at 10.5% (95% CI 6.8-14.3%) in the 45-54 year age category. Diabetes mellitus (DM) correlates were: 13.1% smoking, 74.9% alcohol consumption, 75.7% high level of physical activity; 16.3% obese and 29% overweight with higher rates in women.Among persons with diabetes the odds of obesity, elevated waist circumference and hypertension were three, two and three fold respectively compared to those without diabetes. Cardiovascular risk factors among subjects with diabetes were high and mirrored that of the entire sample; however they had a significantly higher use of tobacco. CONCLUSIONS: This previously unstudied urban slum has a high prevalence of DM yet low screening rates. Key correlates include cigarette smoking and high alcohol consumption. However high levels of physical activity were also reported. Findings have important implications for NCD prevention and care. For this rapidly growing youthful urban slum population policy makers need to focus their attention on strategies that address not just communicable diseases but non communicable diseases as well.