Early nutrition in preterm infants and later blood pressure: two cohorts after randomised trials

Despite data relating body size in early life to later cardiovascular outcomes, the hypothesis that nutrition affects such outcomes has not been established. Breastfeeding has been associated with lower blood pressure in later life, but previous studies have not controlled for possible confounding factors by using a randomised design with prospective follow-up. We undertook such a study to test the hypothesis that early diet programmes blood pressure in later life in children randomly assigned different diets at birth.

Blood pressure was measured at age 13-16 years in 216 (23%) of a cohort of 926 children who were born prematurely and had participated at birth in two parallel randomised trials in five neonatal units in the UK. Dietary interventions were: donated banked breastmilk versus preterm formula and standard term formula versus preterm formula.

Children followed up at age 13-16 years were similar to those not followed up in terms of social class and anthropometry at birth. Mean arterial blood pressure at age 13-16 years was lower in the 66 children assigned banked breastmilk (alone or in addition to mother's milk) than in the 64 assigned preterm formula (mean 81.9 [SD 7.8] vs 86.1 [6.5] mm Hg; 95% CI for difference -6.6 to -1.6; p=0.001). In non-randomised analyses, the proportion of enteral intake as human milk in the neonatal period was inversely related to later mean arterial pressure (beta=-0.3 mm Hg per 10% increase [95% CI -0.5 to -0.1]; p=0.006). No differences were found in the term formula (n=44) versus preterm formula (n=42) comparison.

Breastmilk consumption was associated with lower later blood pressure in children born prematurely. Our data provide experimental evidence of programming of a cardiovascular risk factor by early diet and further support the long-term beneficial effects of breastmilk.