A randomized breast-feeding promotion intervention did not reduce child obesity in Belarus.

The evidence that breast-feeding protects against obesity is based on observational studies, with potential for confounding and selection bias. This article summarizes a previously published study in which we assessed whether an intervention designed to promote exclusive and prolonged breast-feeding affects children's height, weight, adiposity, and blood pressure (BP) at age 6.5 y. The Promotion of Breastfeeding Intervention Trial (PROBIT) is a cluster-randomized trial of a breast-feeding promotion intervention based on the WHO/UNICEF Baby-Friendly Hospital Initiative. A total of 17,046 healthy breast-fed infants were enrolled from 31 Belarussian maternity hospitals and affiliated clinics, of whom 13,889 (81.5%) were followed up at 6.5 y with duplicate measurements of height, weight, waist circumference, triceps and subscapular skinfold thicknesses, systolic and diastolic BP. Analysis was based on intention to treat, with statistical adjustment for clustering within hospitals/clinics to permit inferences at the individual level. The experimental intervention led to a large increase in exclusive breast-feeding at 3 mo (43.3% vs. 6.4%, P < 0.001) and a significantly higher prevalence of any breast-feeding throughout infancy. No significant intervention effects were observed on height, BMI, adiposity measures, or BP. The breast-feeding promotion intervention resulted in substantial increases in the duration and exclusivity of breast-feeding yet did not reduce measures of adiposity at age 6.5 y. Previous reports of protective effects against obesity may reflect uncontrolled bias caused by confounding and selection.

Effects of prolonged and exclusive breastfeeding on child height, weight, adiposity, and blood pressure at age 6.5 y: evidence from a large randomized trial.

BACKGROUND: The evidence that breastfeeding protects against obesity and a variety of chronic diseases comes almost entirely from observational studies, which have a potential for bias due to confounding, selection bias, and selective publication. OBJECTIVE: We assessed whether an intervention designed to promote exclusive and prolonged breastfeeding affects children's height, weight, adiposity, and blood pressure at age 6.5 y. DESIGN: The Promotion of Breastfeeding Intervention Trial (PROBIT) is a cluster-randomized trial of a breastfeeding promotion intervention based on the WHO/UNICEF Baby-Friendly Hospital Initiative. A total of 17,046 healthy breastfed infants were enrolled from 31 Belarussian maternity hospitals and their affiliated clinics; of those infants, 13,889 (81.5%) were followed up at 6.5 y with duplicate measurements of anthropometric variables and blood pressure. Analysis was based on intention to treat, with statistical adjustment for clustering within hospitals or clinics to permit inferences at the individual level. RESULTS: The experimental intervention led to a much greater prevalence of exclusive breastfeeding at 3 mo in the experimental than in the control group (43.3% and 6.4%, respectively; P < 0.001) and a higher prevalence of any breastfeeding throughout infancy. No significant intervention effects were observed on height, body mass index, waist or hip circumference, triceps or subscapular skinfold thickness, or systolic or diastolic blood pressure. CONCLUSIONS: The breastfeeding promotion intervention resulted in substantial increases in the duration and exclusivity of breastfeeding, yet it did not reduce the measures of adiposity, increase stature, or reduce blood pressure at age 6.5 y in the experimental group. Previously reported beneficial effects on these outcomes may be the result of uncontrolled confounding and selection bias.

Effect of prolonged and exclusive breast feeding on risk of allergy and asthma: cluster randomised trial.

OBJECTIVE: To assess whether exclusive and prolonged breast feeding reduces the risk of childhood asthma and allergy by age 6.5 years. DESIGN: Cluster randomised trial. SETTING: 31 Belarussian maternity hospitals and their affiliated polyclinics. PARTICIPANTS: A total of 17,046 mother-infant pairs were enrolled, of whom 13,889 (81.5%) were followed up at age 6.5 years. INTERVENTION: Breastfeeding promotion intervention modelled on the WHO/UNICEF baby friendly hospital initiative. MAIN OUTCOME MEASURES: International study of asthma and allergies in childhood (ISAAC) questionnaire and skin prick tests of five inhalant antigens. RESULTS: The experimental intervention led to a large increase in exclusive breast feeding at 3 months (44.3% v 6.4%; P<0.001) and a significantly higher prevalence of any breast feeding at all ages up to and including 12 months. The experimental group had no reduction in risks of allergic symptoms and diagnoses or positive skin prick tests. In fact, after exclusion of six sites (three experimental and three control) with suspiciously high rates of positive skin prick tests, risks were significantly increased in the experimental group for four of the five antigens. CONCLUSIONS: These results do not support a protective effect of prolonged and exclusive breast feeding on asthma or allergy. TRIAL REGISTRATION: Current Controlled Trials ISRCTN37687716 [controlled-trials.com].