The Association Between Childhood Asthma and Breastfeeding
by Anne Eglash MD, IBCLC, FABM
The research on the relationship between asthma and breastfeeding has been a pendulum. Some researchers have found a dose-response relationship and others have not. This is probably due to the existence of other factors that increase the risk of asthma such as exposure to cigarette smoke, air pollution, early respiratory infection, family history, and timing of complementary feeding. According to the authors of this week’s study, there have been 3 systematic reviews/meta-analyses published in the past 10 years, with 2 demonstrating less asthma with breastfeeding, and one not finding an association. The authors suggest that the previous systematic reviews/meta-analyses included low quality studies and studies with unclear definitions of wheezing.
The systematic review and meta-analysis discussed for today’s clinical question included cohort studies only. Although they attempted to include randomized controlled trials, they didn’t find any- not surprising, as it is hard to randomize many months of breastfeeding vs not breastfeeding. The diagnosis of asthma had to be made by a physician or the symptoms had to meet strict guidelines defined by the study.
The researchers included 42 articles, of which 33% were considered good quality and 38% fair quality.
They found that overall, more breastfeeding was associated with a lower risk of asthma.
What about the details? See the question!
- Among children under age 7, exclusive breastfeeding for 6 months or longer was associated with a 30% lower risk of asthma as compared to exclusive breastfeeding for less than 6 months.
- More breastfeeding was associated with less asthma in children ages 7-12 years of age.
- Any breastfeeding for at least 3 months was associated with a 21% lower risk of asthma compared to any breastfeeding for less than 3 months.
See the Answer
Abstract
Objective
To investigate the relationship between breastfeeding and the development of pediatric asthma.
Methods
A systematic review and meta-analysis was conducted with MEDLINE, EMBASE, CINAHL and ProQuest Nursing and Allied Health source databases. Retrospective/prospective cohorts in children <18 years old with breastfeeding exposure reported were included. The primary outcome was a diagnosis of asthma by a physician or using a guideline-based criterion. A secondary outcome was asthma severity.
Results
Forty-two studies met inclusion criteria. Thirty-seven studies reported the primary outcome of physician/guideline-diagnosed asthma, and five studies reported effects on asthma severity. Children with longer duration/more breastfeeding compared to less have a lower risk of asthma (OR=0.84; 95% CI: 0.75–0.93, I2=62.4%). Similarly, a lower risk of asthma was found in children who had more exclusive breastfeeding versus less exclusive breastfeeding (0.81; 0.72–0.91, I2=44%). Further stratified analysis of different age groups demonstrated a lower risk of asthma in the 0–2 age group (0.73; 0.63–0.83) and the 3–6 age group (0.69; 0.55–0.87), there was no statistically significant effect on the 7+ age group.
Conclusion
The finding suggests that the duration and exclusivity of breastfeeding are associated with a lower risk of asthma in children less than seven years of age.
This is not the first study to show that breastfeeding does not protect from later-onset asthma after age 7 years. A Canadian cohort study also demonstrated that breastfeeding protected from early onset asthma rather than late onset. This might have to do with ongoing environment exposures that increase the risk of asthma over time.
The data regarding protection from asthma with exclusive breastfeeding was derived from only 2 studies, as exclusive breastfeeding rates to 6 months are hard to achieve.
When I discuss the role of breastfeeding in the protection from asthma with my patients, I explain that breastfed children tend to have a later onset of asthma. When parents are contemplating early weaning especially during seasons of respiratory illness, I point out that continued lactation will prevent office visits for wheezing, fewer sleepless scary nights of wheezing, and fewer missed days from work. From my experience, these conversations have had a positive impact on duration of lactation, even if the parent(s) decide to partially wean, such as pumping 2-3 times a day to provide milk.
Irena Zakarija-Grkovic
This is a typical example of incorrect use of associations in the title of the article. It should read ‘Formual feeding and risk of childhood asthma…’, not ‘Breastfeeding’. We need to watch our language, as Diane Weissenger so aptly explains.
Erin
Non of those seemed correct
IABLE
Hmm- A and C are correct according to this research study