Coronary heart disease risk factors in sub-Saharan Africa: studies in Tanzanian adolescents

Abstract

Study objective: To assess the level of cardiovascular risk factors in young people in sub-Saharan Africa living in rural and urban settings.

Design: Cross sectional survey of the population aged 15 to 19 years.

Setting: Eight rural Tanzanian villages in three regions, and two districts in Dar es Salaam.

Participants: 664 males and 803 females in rural villages and 85 males and 121 females in the city. Response rates for total population were 74% to 94% in the rural areas and 60% in the city.

Measurements and results: Measurements included blood pressure, body mass index, serum lipids, and blood glucose concentrations (fasting and two hours after 75 g glucose). Blood pressure was slightly but significantly higher in young women than in young men (115/67 mmHg versus 113/65 mmHg) and increased significantly with age. Only 0.4% subjects had blood pressure greater than 140 and/or 90 mmHg. There were no urban-rural differences. Body mass index was higher in females (mean (SD) 20.3 (2.8) kg/m2) than males (18.5 (2.1)). Overweight was found in only 0.6% at age 15 years but 5.4% at age 19 years. Serum cholesterol concentrations were low at 3.5 mmol/l in males and 3.7 mmol/l in females. Only 7% had values above 5.2 mmol/l. The highest concentrations were found in the city and in Kilimanjaro, the most prosperous rural region. Serum triglycerides were 1.0 (0.5) mmol/l in males and 1.1 (0.5) mmol/l in females, and were highest in the city dwellers. Diabetes was rare (0.28% males, 0.12% females) but impaired glucose tolerance was present in 4.7% and 4.1% respectively. Drinking alcohol was equally prevalent in males and females, reaching 30% at age 19 years. Only 0.4% of females smoked compared with 7.3% of males. Smoking was commoner in rural areas that in the city.

Conclusions: Several risk factors for cardiovascular disease were found in Tanzanian adolescents, but levels were much lower than in studies reported from developed nations. The challenge is to maintain these low levels as the population becomes more urbanised and more affluent.