Effect of an intervention to promote breastfeeding on asthma, lung function and atopic eczema at age 16 years

Abstract

Importance: Atopic diseases, including asthma and atopic eczema, are the most common chronic conditions of childhood.Objective: To investigate whether an intervention to promote prolonged and exclusive breastfeeding protects against asthma, atopic eczema and low lung function in adolescence.Design, Setting, and Participants: Follow-up of a cluster-randomized trial in 30 Belarusian maternity hospitals and affiliated polyclinics; recruitment of 17,046 healthy term infants took place June 1996-December 1997.Intervention: Randomization to receive a breastfeeding promotion intervention vs. usual careMain Outcomes and Measures: Spirometry and flexural eczema on standardized skin examination by study paediatricians were primary outcomes; secondary outcomes were self-reported asthma diagnosis ever, and wheeze and flexural eczema symptoms in the previous year.Results: 13,557 (79.5%) participants were followed up September 2012-July 2015. The intervention (n=7064, 79.7%) and control (n=6493, 79.4%) groups were similar at follow-up (50.8%/52.5% male, mean (SD) age 16.2 (0.6)/16.1 (0.5) years). In the intervention group, 0.3% (21/7064) had flexural eczema on skin examination and mean (SD) FEV1/FVC ratio z-score was -0.10 (1.82), compared to 0.7% (43/6493) and 0.35 (1.34) respectively in the control group. In modified intention-to-treat analysis, accounting for clustering by polyclinic, a 54% lower risk of flexural eczema on skin examination was observed in the intervention compared with the control group (OR, 0.46; 95% CI: 0.25, 0.86). Self-reported flexural eczema symptoms in the past year (OR, 0.57; 95% CI: 0.27, 1.18), asthma (OR, 0.76; 95% CI: 0.47, 1.23) and wheezing in the past year (OR, 0.66; 95% CI: 0.37, 1.18) were less frequently reported in the intervention compared with the control group, but confidence intervals were wide and included the null. There was no difference in FEV1/FVC ratio z-score (beta -0.15; 95% CI: -0.76, 0.45). All results were similar with additional adjustment for baseline characteristics, on instrumental variable analysis, and with multiple imputation among all 17,046 randomized participants.<br/