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Breastfeeding reduces the risk of lower respiratory tract infections and asthma in infants

March 17, 2022

3 minute read

Disclosures:
Rosas-Salazar does not report any relevant financial information. Please see the study for relevant financial information from all other authors.

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According to a study published in The Journal of Allergy and Clinical Immunology.

“The impact of breastfeeding on certain childhood respiratory diseases is still controversial, with some studies actually showing that breastfeeding may increase the risk of certain chronic lung diseases in children, such as asthma,” Christian Rosas-Salazar, MD, MPH, assistant professor of pediatrics at Vanderbilt University Medical Center, Healio said.

To better understand the effect of breastfeeding on pediatric respiratory health, Rosas-Salazar and colleagues assessed data from 1,949 healthy infants (median age, 55 days; interquartile range [IQR], 16-78 days; 47.67% girls; 65.11% non-Hispanic white; 31.4% born by Caesarean section) in a population-based cohort who were followed up via passive and active surveillance, including in-person visits for respiratory disease and viral testing, between November and March of their first year. Only 1,495 (76.71%) of enrolled infants had 4-year data.

The researchers also monitored cytokines in the upper respiratory tract (URT) and gut microbiomes of these infants, while parents reported the type of food they provided to their infants as well as the duration of any breastfeeding.

The median duration of exclusive breastfeeding among all enrolled infants was 6 weeks (IQR, 0-20 weeks).

The URT and gut microbiomes of infants who had been exclusively breastfed had the lowest values ​​of alpha diversity metrics at the time of enrollment. Also at enrollment, beta diversity of URT and gut microbiomes differed by diet type (P

The researchers also found associations between the type of breastfeeding and the levels of pro-inflammatory cytokines, but not with the levels of pro-allergic cytokines.

Overall, 440 infants (22.58%) developed lower respiratory tract infection (LRTI) during infancy, 209 (10.72%) developed food sensitization by one year, 286 (14. 67%) developed current asthma for 4 years and 516 (26.48%) developed allergic rhinitis for 4 years.

Analyzes also showed a dose-response effect of feeding type at enrollment on LRTI in infancy and current 4-year-old asthma, with infants who were exclusively breastfed at enrollment having the odds the weakest of these results. However, there was no association between diet type at enrollment and 1-year food sensitization or 4-year allergic rhinitis.

In addition, duration of exclusive breastfeeding had a protective dose-response effect on LRTI during infancy, current asthma for 4 years, and allergic rhinitis for 4 years. Every 4 weeks of exclusive breastfeeding decreased the risk of LRTI during infancy (OR = 0.95; 95% CI, 0.91-0.99), current asthma at 4 years (OR = 0.95; 95% CI, 0.9-0.99) and at 4 years allergic rhinitis (OR = 0.95; 95% CI, 0.92-0.99) about 5%.

Exploratory analyzes further showed a significant mediating effect of beta diversity in the gut microbiome, but not the URT microbiome, on the association between exclusive breastfeeding and current 4-year-old asthma.

Beta diversity of URT and gut microbiomes in early life, as well as URT cytokines in infancy, showed no mediating effect on associations between exclusive breastfeeding and other clinical outcomes.

Christian Rosas-Salazar

“The results of our study suggest that exclusive breastfeeding protects against the risk of lower respiratory tract infections such as bronchiolitis or pneumonia, asthma and hay fever in young children,” said Rosas- Salazar. “Furthermore, we show that these effects are likely due to the impact of exclusive breastfeeding on the microbiome in early life.”

Noting these benefits, the researchers recommended that physicians discuss the effects of breastfeeding on respiratory health with their patients.

“Health care providers should continue to strongly recommend exclusive breastfeeding to their patients, and they can add the protective effects of exclusive breastfeeding on common childhood respiratory illnesses as one of the potential benefits,” Rosas said. -Salazar.

Longer durations of exclusive breastfeeding likely offer the most protection, the researchers continued, with nonexclusive breastfeeding in the first few months possibly offering benefits as well.

“Understanding whether exclusive breastfeeding impacts the development of lung disease in older children or even adults is an important next step for our study,” Rosas-Salazar said.

For more information:

Christian Rosas-Salazar, MD, MPH, can be reached at [email protected]