Nutritional variation and cardiovascular risk factors in Tanzania--rural-urban difference

To assess the relationship between dietary factors and cardiovascular (CVD) risk factors in middle-aged men and women, in urban, rural and pastoral settings in Tanzania.

Cross-sectional epidemiological study designed according to the protocol of the World Health Organisation (WHO) Cardiovascular Diseases and Alimentary Comparison (CARDIAC) study.

Three centres in Tanzania, namely Dar es Salaam (urban), Handeni (rural) and Monduli (pastoral population).

The subjects, aged 47-57 years, were recruited randomly from administrative lists available from each centre.

Blood pressure (BP) was measured using a centrally calibrated automatic BP machine (Khi machine). Dietary history of the participants was obtained using a standard questionnaire designed on the basis of a seven-day recall system. Height, weight, serum total cholesterol (TC) and high-density lipoprotein cholesterol (HDLC), haemoglobin A1c, sodium, potassium and magnesium were measured.

The prevalence of hypertension (BP > or = 140/90 mmHg or antihypertensive drug use), obesity (body mass index (BMI) > or = 30 kg/m2) and hypercholesterolaemia (TC > 5.2 mmol/l) were lowest in the rural area. Consumption of green vegetables, milk, coconut milk, meat, and fish varied significantly between the three areas. Important determinants for BP among men were BMI (p < 0.001), and salt intake (p < 0.05). Among women, TC (p < 0.05), age (p < 0.05), BMI (p < 0.001) and coconut milk consumption (p < 0.001) were important BP determinants. Salt intake was positively associated with systolic BP (SBP) and diastolic BP (DBP) in men but not among women (both SBP and DBP p < 0.05 respectively). Dietary determinants of serum TC were meat, fish and green vegetable consumption.

Differences in dietary habits contributed significantly to the urban-rural-pastoral variations in CVD risk pattern in Tanzania.