Breastfeeding duration and blood pressure among Brazilian adolescents

Objective: To assess the relationship between breastfeeding duration and blood pressure in a large birth cohort of Brazilians followed from birth to adolescence. Methods: All 5914 hospital births occurring in Pelotas in 1982 (over 99% of all deliveries) were studied prospectively. Detailed information on feeding practices was prospectively collected during childhood. In 1997 and 2001 we attempted to trace a sample of the cohort, whereas in 2000 we identified the male subjects when presenting for the army recruitment exam. Blood pressure measurements were taken in 1997 for both sexes, males in 2000 and females in 2001. Results: Information on breastfeeding collected between 1983 and 1986 was available for 90.8% of the 5914 original cohort subjects. We managed to follow 1076, 2250 and 1031 subjects in 1997, 2000 and 2001, respectively. Total breastfeeding duration was not associated with systolic and diastolic blood pressure in adolescence. Diastolic blood pressure at the age of 15 y (1997) was higher among girls who had been predominantly breastfed for at least 4 mo. After controlling for confounding variables (family income, maternal education at birth and maternal BMI at birth, skin colour, birthweight, gestational age, maternal smoking during pregnancy, adolescent smoking and alcohol drinking), the strength of the association was reduced and the 95% confidence interval encompassed the other blood pressure estimates. Furthermore, such association was not replicated in the 2001 follow-up visit.

Conclusion: Breastfeeding duration was not related to blood pressure in adolescence.