Breastfeeding and wheeze prevalence in pre-schoolers and pre-adolescents: the Genesis and Healthy Growth studies

Background: To date, extensive research has been undertaken on a potential link of breastfeeding (BF) to wheezing illnesses. Nevertheless, an association remains to be established, partly due to age-dependent discrepancies and different definitions of exposures/outcomes across studies. We thus investigated the relation of diverse infantile feeding patterns with wheeze/asthma prevalence in two cohorts of children of different ages (preschool and preadolescent).

Methods: Wheeze ever/in the last 12 months (current) and doctor-diagnosed asthma were retrospectively reported by parents of the participants of two cross-sectional studies: the Genesis study (1871 children aged 1-5) and the Healthy Growth study (1884 children aged 9-13). Information on feeding practices (exclusive breastfeeding vs. mixed vs. formula feeding) and their duration (2 vs. 4 vs. 6 months) was recorded. Perinatal and anthorpometric data were also collected.

Results: In pre-schoolers, regimes that did not entail exclusive BF were positively correlated to current/ever wheeze, both before and after adjustment for confounders. No differences between the associations of regimes with 2, 4 or 6 months of exclusive BF with current/ever wheeze were shown. Furthermore, there was no consistent correlation of feeding practices with physician-diagnosed asthma. In pre-adolescents, no association of infantile feeding patterns with the wheeze/asthma outcomes was observed.

Conclusions: Exclusive BF is associated with reduced prevalence of current/ever wheeze in pre-schoolers; however, this appears to wane in older children. The association of a period of exclusive BF as low as 2 months with pre-school wheeze prevalence, appeared to be comparable with that of 6 months of exclusivity.