An inverse relation between blood pressure and birth weight among 5 year old children from Soweto, South Africa

Study objective-To examine the relation between birth weight and blood pres sure at 5 years in a cohort of South African children. Design-Prospective cohort study. Participants-849 five year old children. Setting-Soweto, a sprawling urban area close to Johannesburg, South Africa, which was a designated residential area for people classified as "black" u nder apartheid legislation. Main results-Systolic blood pressure at 5 years was inversely related to bi rthweight (r=-0.05, p=0.0007), independent of current weight, height, gesta tional age, maternal age or socioeconomic status at 5 years. There was no r elation between birth weight and diastolic blood pressure. After adjusting for current weight and height, there was a mean decline in systolic blood p ressure of 3.4 mm Hg (95% confidence intervals 1.4, 5.3 mm Hg) for every 10 00 g increase in birth weight. Conclusions These data from a disadvantaged urbanised community in Southern Africa extend the reported observations of an inverse relation between bir th weight and systolic blood pressure. The study adds to the evidence that influences in fetal life and early childhood influence systolic blood press ure. Further research is required to assess whether efforts to reduce the i ncidence of low birthweight babies will attenuate the prevalence of hyperte nsion in future generations.