Dr. Mary Schooling, professor at the CUNY Graduate School of Public Health and Health Policy, along with colleagues from China examined the association of breast feeding with infant growth and body mass index to age 16 years. The work was published in the journal Paediatric and Perinatal Epidemiology.
[Photo: Dr. Mary Schooling]
Controversial findings concerning associations of breast feeding with growth have been reported. This study examined the associations of breast feeding with early growth trajectories and body mass index to 16 years, in a unique population with little association of socio-economic position with breastfeeding, using a study which has replicated and extended many of the findings of the PROBIT randomized controlled trial of breastfeeding prevention.
The research team utilized the Hong Kong’s ‘Children of 1997’ population-representative birth cohort for this study. They classified contemporaneously reported breast-feeding status in the first 3 months as exclusive breast feeding (n = 470), mixed feeding (n = 2693), and formula feeding (n = 4204). They used linear regression and mixed modeling to assess adjusted sex- and age-specific associations of breast feeding with infant growth (gains in weight-for-age z scores, length/height-for-age z scores, and body-mass-index-for-age z score based on the World Health Organization standards/references from birth to 36 months). The team used generalized estimating equations to assess adjusted sex-specific associations of breast feeding with average body-mass-index-for-age z score from 3 months to 16 years were assessed using generalized estimating equation. Potential confounders were maternal and infant characteristics, and household income.
Among 7367 children, as expected greater weight-for-age z scores gains were observed in exclusively breast fed infants from 0 to 3 months than in formula fed infants but greater gains were seen in formula fed than breast fed infants from 3 to 9 months. Breast feeding was not associated with overall body-mass-index-for-age z score from 3 months to 16 years, with no differences by sex.
The research team concluded that their findings suggested that breast feeding may only have short-term effects on growth. They felt the need for further studies of the role of breast feeding in other metabolic diseases would be a logical next step.