Systematic review and meta‐analysis investigating breast feeding and childhood wheezing illness

Abstract

There is conflicting evidence concerning the relationship between breast feeding and wheezing illness. The objective of this study was to investigate whether there is any association between breast feeding and wheezing in children aged over 5 years and to discover possible sources of heterogeneity. An electronic search of MEDLINE and EMBASE databases was conducted from January 2000 to June 2010. In addition, reference lists from relevant publications were searched. Birth cohort, cross-sectional and case-control studies were included if they measured any breast feeding or exclusive breast feeding for 3 or 4 months. Wheezing illness, including asthma, was identified based on symptoms, reported diagnosis or objective criteria. Thirty-one publications were identified for meta-analysis. There was no association found between any or exclusive breast feeding and wheezing illness, although there was a high level of heterogeneity between the studies. Subgroup analysis revealed that any breast feeding slightly lowers the odds of wheeze (pooled odds ratio 0.92 [0.86, 0.98]) but slightly increases the odds of asthma defined by specific criteria (pooled odds ratio 1.10 [1.00, 1.22]). This meta-analysis does not provide evidence that breast feeding is protective against wheezing illness in children aged 5 years and over. The difference in the effects of breast feeding according to the nature of the wheezing illness highlights the importance of the heterogeneity of illness phenotypes.

Breastfeeding is protective against early childhood asthma

“…Previous studies examining the protective effect of breastfeeding on asthma at older ages showed conflicting results. Some studies observed that breastfeeding was associated with a decreased risk of asthma,3 4 and others did not,5 6 or saw even an increased risk of asthma in school-aged children and adulthood 7 8. Also, the increased protective effect of breastfeeding on asthma in atopic children remains debatable as earlier studies, including a recent meta-analysis, observed more or less protective effects of breastfeeding on asthma in school-aged atopic children or children with a family history of asthma 6–8.…”

Breastfeeding and Asthmatic Symptoms in The Offspring of Latinas: The Role of Maternal Nativity

“…Some studies have found either no or an increased risk of asthma with breastfeeding (20–22). These inconsistencies may be due to differences in phenotypes and related to the age of the child.…”

“…Also, we have a sample rich in covariate information linked to birth certificate data for multivariate adjustment, including detailed duration of exclusive breastfeeding, daycare attendance, parental atopy, pets, and child bronchitis/cold and flu history. These latter covariates allowed us to explore the hypothesis that the benefits from breastfeeding might be due to a reduction in virus-associated wheeze (9,22). However, including both bronchitis and severe cold/flu prior to one year in our models did not change the estimate for breastfeeding.…”

Breastfeeding, Childhood Asthma, and Allergic Disease

“…A review that included all study types published in 2011 considering breastfeeding and wheezing illness beyond 5 years of age only showed no association, highlighting an enormous controversy in this area [27] . The authors of this review recommend that further studies should aim to be of the highest quality and specific diagnostic criteria for asthma to be included.…”