Breastfeeding does not protect against childhood obesity

Breastfeeding has many advantages, but population strategies to increase the duration and exclusivity of breastfeeding are unlikely to curb the obesity epidemic. That is the conclusion of a study published on the Web site of the Journal of the American Medical Association on March 13, 2013. 

Thirty-one Belarusian maternity hospitals and their affiliated clinics were included in the cluster-randomized controlled trial. The subjects were randomized into 1 of 2 groups: breastfeeding promotion intervention (n=16) or usual practices (n=15). Participants were 17,046 breastfeeding mother-infant pairs enrolled in 1996 and 1997, of whom 13,879 (81.4%) were followed up between January 2008 and December 2010 at a median age of 11.5 years.

The children were evaluated for body mass index (BMI), fat and fat-free mass indices (FMI and FFMI), percent body fat, waist circumference, triceps and subscapular skinfold thicknesses, overweight and obesity, and whole-blood IGF-I.

Although the experimental intervention substantially increased breastfeeding duration and exclusivity when compared with the control group (43% vs 6% exclusively breastfed at 3 months and 7.9% vs 0.6% at 6 months), it did not prevent overweight or obesity in the children who had been breastfed. 

Cluster-adjusted mean differences in outcomes at age 11.5 years between the experimental and control groups were: 0.19 (95% CI, –0.09 to 0.46) for BMI; 0.12

(–0.03 to 0.28) for FMI; 0.04 (–0.11 to 0.18) for FFMI; 0.47% (–0.11% to 1.05%) for percent body fat; 0.30 cm (–1.41 to 2.01) for waist circumference; –0.07 mm (–1.71 to 1.57) for triceps and –0.02 mm (–0.79 to 0.75) for subscapular skinfold thicknesses; and –0.02 standard deviations (–0.12 to 0.08) for IGF-I.

Martin RM, Patel R, Kramer MS, et al. Effects of promoting longer-term and exclusive breastfeeding on adiposity and insulin-like growth factor-I at age 11.5 years: A randomized trial. JAMA. 2013;309(10):1005-1013.