Mothers who participated in a breastfeeding intervention trial had teenagers with lower risk of eczema, but not asthma, a large Belarusian follow-up study found.
Adolescents whose mothers were part of the breastfeeding intervention group had about a 50% reduction in the risk of flexural eczema compared with those whose mothers received standard care (adjusted OR 0.46, 95% CI 0.25-0.83), reported Carsten Flohr, MD, PhD, of King’s College in London, and colleagues.
But there was no evidence of an association between the intervention group and either self-reported atopic eczema symptoms or asthma outcomes in the past year, the authors wrote in JAMA Pediatrics.
They noted that many allergy organizations and the World Health Organization (WHO) recommend exclusive breastfeeding for the first 4 to 6 months of life “to aid the prevention of allergy and associated illnesses,” but added that these recommendations are based on contradictory results and “inconsistent” findings of cross-sectional studies with methodological shortcomings.
While a trial that examined the impact of a breastfeeding intervention found “marked differences in breastfeeding exclusivity and duration,” the authors saw a unique opportunity to follow-up with these trial participants “to test the long-term effects of breastfeeding on childhood outcomes, including asthma, lung function and atopic eczema.”
This study was a follow-up of the Promotion of Breastfeeding Intervention Trial (PROBIT), a cluster randomized clinical trial of breastfeeding promotion conducted at 34 Belarusian maternity hospitals. Intervention was determined by hospitals who were either randomized to implement an experimental breastfeeding intervention or to implement standard care.
Risk of gastrointestinal tract infection was the primary outcome of the trial, with risk of atopic eczema a secondary outcome. Children were followed up for 12 months from the time of birth, and when they were about age 6 years, using skin-prick tests and the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire to get information about asthma and atopic eczema. There was a third follow-up when the children were almost age 12 years, though this did not include atopy-related outcomes, the authors said.
During this current follow-up, children were physically examined for evidence of flexural dermatitis, reported their atopic eczema and asthma symptoms using the ISAAC questionnaire, and had their lung function measured by spirometry.
Overall, 13,557 participants — about 80% of the original cohort — were followed up at age 16 years. There were 7,064 from the intervention group and 6,493 from the control group. Both groups had about equal representation between boys and girls.
In an intention-to-treat analysis, there were 21 (0.3%) children with signs of flexural eczema in the intervention group compared with 43 (0.7%) of the control group. But when examining secondary outcomes, the authors noted an odds ratio of “similar magnitude, but with lower precision.”
- Questionnaire-derived flexural eczema in past year: cluster-adjusted OR 0.57 (95% CI 0.27-1.18)
- Persistent flexural eczema in past year: cluster-adjusted OR 0.48 (95% CI 0.22-1.04)
- Sleep-disturbed flexural eczema in past year: cluster-adjusted OR 0.54 (95% CI 0.23-1.28)
Similar results were seen for asthma outcomes, where the authors found no protective effect for breastfeeding. Overall, 108 (1.5%) of the intervention group reported “asthma ever” versus 110 of the control group (1.7%), but with similar wide estimates (cluster-adjusted OR 0.66, 95% CI 0.37-1.18).
Researchers also found no significant difference in reported asthma attacks in the past 12 months, and they noted that effect estimates for “asthma ever” and wheezing in the past 12 months were similar after adjustment.
Limitations to the data include unconscious bias in skin examination, if the pediatrician was aware of the child’s treatment allocation, and there was no ability for quality assurance of measured lung function equipment, “due to technical limitations of the equipment used in the field,” the authors said. They also noted that atopic eczema is less common in Belarus compared with North America and Western Europe, and their centralized healthcare system is also different, which could potentially limit the generalizability of the findings.
The study was supported in by EU grants, the Canadian Institutes of Health Research, and the NIH.
Flohr disclosed funding from the National Institute for Health Research (NIHR) and the NIHR Biomedical Research Centre, and no relevant relationships with industry.
Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner