Association of birth weight and breast-feeding with coronary heart disease risk factors at the age of 6 years

Background and Aim: It has been shown that early growth and nutrition affect health in childhood and later life. The aim of this study was to assess the association of birth weight and breast-feeding in infancy with body mass index (BMI) and serum lipids at the age of six years. The contributions of current macronutrient intake, maternal age and BMI were assessed. Methods and Results: This was a longitudinal observational study of 120 randomly chosen children whose birth weight and duration of breast-feeding had been recorded. At the age of six years, their weight and height, and serum cholesterol (total, LDL and HDL) and triglyceride levels were measured at healthcare centres in Iceland. Dietary intake at six years was estimated using 3-day weighed food records. The duration of breast-feeding negatively correlated with BMI in 6-year-old boys (B=-0.19±0.07, p=0.011) but not in girls; after adjusting for maternal BMI, the relationship in boys was of borderline significance (p=0.087). The 6-year-old boys who had been breast-fed for <5 months had a significantly higher BMI (18.0 ± 2.5 kg/m²) than those breast-fed for 8-9 months (15.8 ± 1.2 kg/m², p=0.006) or ≥10 months (15.7 ± 1.2 kg/m², p=0.005). A longer duration of breast-feeding was related to higher HDL-cholesterol levels in 6-year-old girls (B=0.03±0.01, p=0.032), but not boys. Birth weight was not related to BMI or serum lipid levels at the age of 6 years. Conclusion: In this high birth weight population, a longer duration of breast-feeding may be effective in preventing childhood overweight, at least among boys. Breast-feeding also seems to be related to an improved lipid profile in girls.