The relationship between infant feeding practices and childhood wheezing has been controversial and it is suggested that this may result from insufficient differentiation among various feeding modes. As part of a large national study in the USA – The Infant Feeding Practices Study II – the researchers conducted prospective analyses of associations between the repeated ascertainment of feeding mode and wheezing in infancy in 2,833 infants.

Data was provided by the mother on coughing/wheezing episodes (CWEs) at 8 time points and feeding at 9 time points from months 1 to 12. Feeding was defined as direct breastfeeding, indirect breastfeeding (bottled breastmilk), formula feeding (FF), and their combinations. Following analysis, the relative risks (RR) and their 95% confidence intervals (95% CI) of different feeding modes for CWEs were estimated.

Compared with direct breastfeeding, any other feeding mode showed a statistically significant risk for CWEs and the authors conclude that any mode of feeding that includes formula or bottled breastmilk seems to be a moderate risk for cough or wheezing episodes in the first 12 months of life.

Soto-Ramirez N, Karmaus W, Zhang H et al (2012). Modes of Infant Feeding and the Occurrence of Coughing/Wheezing in the First Year of Life. J Hum Lact. published 22 August 2012, 10.1177/0890334412453083