From Medscape Medical News
Laurie Barclay, MD
June 21, 2010 — Breast-feeding until age 4 months is linked to lower rates of respiratory and gastrointestinal (GI) infection morbidity, according to the results of a population-based, prospective, cohort study reported online June 21 in Pediatrics.
"Exclusive breastfeeding seems to decrease the risk of infectious diseases in infancy," Liesbeth Duijts, MD, PhD, from Erasmus Medical Center in Rotterdam, the Netherlands. "However, the World Health Organization has called for more research regarding the benefits for 6 months instead of 4 months of exclusive breastfeeding."
The goal of this study, which was embedded in the Generation R Study, a study from fetal life onward in the Netherlands, was to evaluate the associations of duration of exclusive breast-feeding with upper respiratory tract infections (URTI), lower respiratory tract infections (LRTI), and GI tract infections in infancy.
There were 4164 subjects who completed questionnaires on rates of breast-feeding during the first 6 months (never; partial for < 4 months, not thereafter; partial for 4 - 6 months; exclusive for 4 months, not thereafter; exclusive for 4 months, partial thereafter; and exclusive for 6 months) and doctor-attended URTI, LRTI, and GI infections until age 12 months.
Risks for URTI, LRTI, and GI tract infection until age 6 months were lower in infants who were breast-fed exclusively until age 4 months and partially thereafter vs infants who were never breast-fed. Adjusted odds ratios (ORs) were 0.65 (95% confidence interval [CI], 0.51 - 0.83) for URTI, 0.50 (95% CI, 0.32 - 0.79) for LRTI, and 0.41 (95% CI, 0.26 -0.64) for GI tract infection. The adjusted OR for LRTIs in infants between the ages of 7 and 12 months was 0.46 (95% CI, 0.31 - 0.69).
For infants who were exclusively breast-fed for at least 6 months, trends were similar. However, partial breast-feeding, even for 6 months, was not associated with significantly lower risks for these infections.
"Exclusive breastfeeding until the age of 4 months and partially thereafter was associated with a significant reduction of respiratory and gastrointestinal morbidity in infants," the study authors write. "Our findings support health policy strategies to promote exclusive breastfeeding for at least 4 months, but preferably 6 months, in industrialized countries."
Limitations of this study include questionnaires with breast-feeding data available for only 65% of eligible participants of the Generation R Study and possible misclassification related to questionnaire use.
"Biological, cultural, and social constraints related to breastfeeding habits need to be studied more extensively," the study authors write. "The effects of prolonged and exclusive breastfeeding on infectious diseases at older ages in industrialized countries remain to be studied."
Exclusive breast-feeding until age 4 months and partially thereafter was associated with a significant reduction of respiratory and GI morbidity rates in infants.
The first phase of the Generation R Study was funded by Erasmus Medical Center, Erasmus University Rotterdam, and Netherlands Organization for Health Research and Development (Zon Mw). The present study was supported by an additional grant from Stichting W. H. Kröger (00–048) and AGS Kinderstichting. The study authors have disclosed no relevant financial relationships.
Pediatrics. Published online June 21, 2010.