Background: Breastfeeding is a well-known protective factor against severe respiratory tract infections. Recently, a gender specific role for human milk has been described in very low birth weight infants and neonates: breast milk protected girls but not boys.
Objective: To determine whether the protective effect of breastfeeding on the severity of acute respiratory infections in full term infants is different for girls and boys.
Methods: A prospective cross-sectional study of infants seeking medical care for acute respiratory infection. The protective role of breastfeeding against viral pneumonia and hospitalization were assessed by univariate and multivariate analyses. Analyses were adjusted for important confounders.
Results: A total of 323 patients were enrolled in this study. Breastfeeding protected girls against pneumonia and hospitalization, but did not protect boys. Nonbreastfeeding females were particularly susceptible to severe acute respiratory infections.
Conclusions: Breastfeeding had a protective effect against severe disease in infant girls experiencing their first symptomatic respiratory infection. Nonbreastfeeding females are at significant risk for severe acute lung disease and should be targeted intensively by breastfeeding campaigns.
From *Fundacion INFANT, Buenos Aires, Argentina; †Department of Pediatrics, Johns Hopkins University, Baltimore, MD; and ‡Hospital Materno Infantil San Isidro, Buenos Aires, Argentina.
Accepted for publication August 14, 2008.
Supported by a National Institute of Environmental Health Sciences contract mechanism with Johns Hopkins University and Fundacion INFANT and AI-054952 (FPP).
The first 2 authors contributed equally to this manuscript.
Address for correspondence: Fernando P. Polack, MD, Department of Pediatrics, Vanderbilt University, 1161 21st Avenue South, Nashville, TN 37232-2905. E-mail: firstname.lastname@example.org.