Relationship between age at giving fortified powdered cow's milk and cessation of breastfeeding on the nutritional status of a Chilean child cohort followed from birth to 3 years of age.

Abstract

To examine how much of the variation in weight-for-height (WHZ) z-scores were associated with age at which breastfeeding ceased and provision of fortified cow's milk (Leche Purita Fortificada, LPF) commenced in a cohort of children studied from birth to 3 years of age. Longitudinal data were obtained from routine medical check-ups on 8373 children from nine Chilean counties through convenience sampling. WHZ z-scores were generated at six-monthly intervals using WHO 2006 standards from birth to 3 years old (seven measurements). Age of cessation of breastfeeding and age of commencement of LPF were the independent variables. Repeated-measures ANOVA were used to analyse the changes in WHZ over the seven measurements. Binomial generalised estimating equations (GEE) were used to analyse the effect of each independent variable on the change from normal to overweight, and normal to obese over the seven measurements. ANOVA indicated that children given LPF milk before 3 months of age had, on average, higher mean WHZ of about 0.11 SD from 18 months of age onwards (p < 0.001). GEE analyses showed that children given LPF before 3 months of age were significantly more likely to be overweight or obese (OR = 1) compared with children given LPF later (overweight OR: 0.809-0.970, p = 0.009, obese (OR: 0.666-0.901, p = 0.001). Early intake of LPF increases WHZ and is a risk factor for overweight and obesity in young children, while prolonged breastfeeding acts as protective factor against obesity.