Good news for breastfed babies –breastfeeding may reduce risk of wheezing and asthma for several years (J Pediatr 2012; 160: 991-6).

In this prospective birth cohort study of 1105 infants from New Zealand, detailed feeding information was obtained at 3, 6, and 15 months which allowed calculation of breastfeeding duration. This information was correlated with information about wheezing and asthma collected at 2, 3, 4, 5, and 6 years.

Findings (after controlling for confounding variables):

• Each month of exclusive breastfeeding was associated with significant reductions in asthma at all timepoints.  The effect was most prominent at younger ages.
• The authors estimate that if every infant in the cohort had been exclusively breastfed for 6 months, that asthma would have been reduced by 50% at 2 years, 42% at 3 years, 30% at 4 years, 42% at 5 years, and 32% at 6 years.
• In atopic children, the effects of exclusive breastfeeding are more pronounced.  In this study, exclusive breastfeeding for ≥3 months reduced asthma at ages 4, 5, and 6 by 62%, 55%, and 59% respectively.

The authors note that not all studies have found that breastfeeding improves asthma.  However, most of these studies reported outcomes in older children.

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More evidence that breastfeeding improves cognitive development

Additional references:

• -NEJM 2011; 364: 701, 769.  Living on a farm decreases risk of childhood asthma.
• -Thorax 2009; 64: 604-9. Breastfeeding and asthma in children followed for 8 years.
• -Br Med J 2007; 335: 815-20.  Longer time of breastfeeding does not reduce allergy/asthma. n=17,046 pairs of mother-infant (13,889 followed up at age 6.5yrs)