Acute bronchiolitis affects around 30 % of infants each winter in France. Breastfeeding (BF) is described as being protective against acute lower respiratory infections in developing countries, but this effect is more difficult to demonstrate in industrialized countries. Moreover, the effect of using a pacifier in the occurrence of bronchiolitis is not clearly established. In this context, the aim of the study was to investigate the link between BF and the use of a pacifier in the occurrence of bronchiolitis in children under 1 year of age who presented to five pediatric emergency centers in Pays de la Loire, France.

A questionnaire collecting data on diet, sociodemographic characteristics, and the reason for presentation was provided at the admission to pediatric emergency centers in five hospitals in Pays de Loire, France, between 2018 and 2020. Children with bronchiolitis were included in group 1, and children consulting for other reasons (except gastrointestinal infections or otitis) were included in group 2. Breastfeeding was classified as exclusive breastfeeding (EBF) and partial breastfeeding (PBF). Pacifier use was classified as frequent and during sleep or not used.

The study included 671 children under 1 year of age, including 174 (25.8 %) who were admitted with bronchiolitis. In univariate analysis, a significantly smaller number of children in group 1 s were breastfed (EBF and PBF) at admission compared with children in group 2:21.8 % versus 32.8 %, respectively, (OR=0.57, 95 % CI: 0.38–0.86, p = 0.006); furthermore, children in group 1 used a pacifier more often than those in group 2: 84.5 % versus 75.8 % (OR=1.74, 95 % CI: 1.10–2.76, p = 0.017). In multivariate analysis, after adjusting for age, ongoing BF or EBF beyond 9 and 12 months of age remained a protective factor; however, the protective effect of BF disappeared with the introduction of a pacifier, and pacifier use was significantly associated with bronchiolitis.

The protective effect of BF against bronchiolitis was demonstrated independently of pacifier use. However, due to the strong association between pacifier use and bronchiolitis, the effect of BF weakened. The advice to be given to parents for BF and pacifier use is discussed.