Determinants of blood pressure in Sowetan infants

A study of the effect of different variables on the blood pressure of Sowetan infants was undertaken with the Birth-to-Ten (BTT) cohort as the study population. Variables studied at 1 year included anthropometric indices, aspects of feeding practices and relationship to maternal blood pressure. Systolic blood pressure was recorded in 792 infants at 1 year; 29,3% of the variance was determined by weight, upper arm circumference, age at which formula feeds were started, length and volume of formula feeds (in order of significance). Amount of salt added to diet approached statistical significance. Data available for 353 of the 752 infants showed a correlation between the infants' and the mothers' blood pressure. The maternal blood pressure only accounted for an additional 2% of the variance; approximately 70% of blood pressure variance is therefore still unexplained. Firm recommendations with regard to use of formula feeds and the addition of salt to infants' diet are difficult to make on the basis of this limited follow-up.