Effect of early exclusive breastfeeding on morbidity among infants born to HIV-negative mothers in Zimbabwe

Background: Early exclusive breastfeeding (EBF) is recommended by the World Health Organization, but EBF rates remain low throughout the world. For infants born to breastfeeding HIV-positive mothers, early EBF is associated with a lower risk of postnatal transmission than is feeding breast milk together with other liquids or foods. No studies conducted in Africa have reported any benefits of EBF for infants born to HIV-negative women. Objective: The objective was to compare the rate of sick clinic visits by infants aged 43-182 d according to breastfeeding exclusivity [EBF, predominant breastfeeding (PBF), and mixed breastfeeding (MBF)]. Design:We compared rates of all-cause clinic visits and clinic visits related to diarrhea and lower respiratory tract infection (LRTI) among a cohort of 9207 infants of HIV-negative mothers during 2 age intervals: 43-91 and 92-182 d according to exclusivity of breastfeeding. Breastfeeding exclusivity was defined in 2 ways ("ever since birth" and "previous 7 d") and was assessed at 43 and 91 d. Results: EBF between birth and 3 mo was significantly protective against diarrhea between 3 and 6 moof age with the "ever since birth" definition [incidence rate ratios (IRRs) of 8.83 (95% CI: 1.07, 65.53) and 8.76 (95% CI: 1.13, 68.09) for PBF and MBF, respectively] and with the "previous 7 d" definition [2.04 (95% CI: 1.11, 3.77) and 2.05 (95% CI: 1.13, 3.72) for PBF and MBF, respectively]. The adverse effect of MBF on LRTI visits was weaker, reaching borderline significance only by the "ever since birth" definition during the 43-91-d interval (IRR: 1.91; 95% CI: 0.99, 3.67). Conclusion: Early EBF is associated with a significant reduction in sick clinic visits, especially those due to diarrhea.