The evidence supporting the relationship between breastfeeding and the development of asthma is conflicting and remains controversial. A large (n=1,105) prospective study was carried out in New Zealand to investigate the effects of breastfeeding on wheezing and current asthma in children 2 to 6 years of age.
Detailed information about infant feeding, including duration of exclusive and any breastfeeding was collected using questionnaires administered at birth and at 3, 6, and 15 months. Information about wheezing and current asthma was collected at 2, 3, 4, 5, and 6 years. Current asthma was defined as ‘‘ever had a doctor’s diagnosis of asthma’’ and ‘‘wheeze in the last 12 months’’ or ‘‘used an inhaler in the last 12 months’’.
The researchers found that after adjustment for confounders, each month of exclusive breastfeeding was associated with significant reductions in current asthma from 2 to 6 years (all, P < .03). Current asthma at 2, 3, and 4 years was also reduced by each month of any breastfeeding (all, P < .005). In atopic children, exclusive breastfeeding for around 3 months reduced current asthma at ages 4, 5, and 6 by 62%, 55%, and 59%, respectively.
There was no evidence that prolonged breastfeeding (exclusive or any) increased the risk of current asthma in any subgroup of children, including atopic children with a maternal history of asthma.
The researchers conclude that breastfeeding, particularly exclusive breastfeeding, protects against current asthma up to 6 years.
Silvers KM, Frampton CM, Wickens K et al on behalf of the New Zealand Asthma and Allergy Cohort Study Group (2012) Breastfeeding Protects against Current Asthma up to 6 Years of Age. The Journal of Pediatrics. Available online 30 January 2012. DOI:10.1016/j.jpeds.2011.11.055
