Bottle-feeding regardless of milk type may affect infant weight outcomes
WASHINGTON — Infants who are exclusively bottle-fed may have an increased risk for rapid weight gain between birth and age 6 months and higher weight-for-length z scores, regardless of milk type, compared with infants who are breastfed, according to study findings presented here.
“The evidence that breast-feeding protects against infant overweight and childhood obesity risk is mixed,” Sally G. Eagleton, MS, a doctoral student in nutritional sciences at Pennsylvania State University, said during her presentation. “One of the reasons for these conflicting results may be due to differences in how previous studies have defined breast-feeding, and studies don’t always distinguish between what infants are being fed or how infants are being fed. More recent studies have started to distinguish between these two unique factors and have shown, irrespective of milk type, that infants experience greater weight gain during the first year when milk feeding comes from a bottle.”
Eagleton and colleagues evaluated data from the Intervention Nurses Start Infants Growing on Healthy Trajectories (INSIGHT) trial, a randomized controlled trial evaluating a responsive parenting intervention that was designed to prevent rapid infant weight gain and early childhood obesity among first-born infants.
“Previous results from the INSIGHT study have shown positive effects of the responsive intervention on infant weight comes across the first year,” Eagleton said. “Specifically, fewer infants in the responsive parenting group had faster weight gain from birth to 6 months compared to infants in the safety control group.”
To build on previous findings, Eagleton and colleagues sought to determine the associations between the percentage of infant feedings as breastmilk and the percentage of feedings from a bottle with rapid weight gain from birth to 6 months and weight-for-length z scores at 1 year.
Participants provided infant feeding information through phone interviews. The percentage of total milk feedings from a bottle at 8 weeks (n = 252) and breastmilk at 16 weeks (n = 267) were calculated. Conditional weight gain scores were used to measure rapid weight gain from birth to 6 months, and 1-year weight-for-length z scores were calculated using WHO 2006 growth charts.
At 8 weeks, 25% of infants were exclusively bottle fed, 13% were exclusively nursed and 62% were mixed fed.
No significant effect of what infants were being fed was observed for rapid weight gain from birth to 6 months; however; a significant effect of how infants were fed was observed for rapid weight gain, suggesting that a greater percentage of bottle feedings was associated with rapid weight gain from birth to 6 months,
Similarly, no significant effect of what infants were fed was observed for weight-for-length z score; however, a significant effect of how infants were fed was observed, suggesting that a greater percentage of bottle feedings was associated with higher z scores.
“Regardless of milk type, bottle feeding may be a unique predictor of early childhood obesity, and these results suggest that importance of a potential to target responsive bottle feeding in future childhood obesity prevention interventions,” Eagleton said. – by Amber Cox
Eagleton SG. T-OR-2024. Presented at: ObesityWeek 2017; Oct. 29-Nov. 2, 2017; Washington, D.C.
Disclosure: Eagleton reports no relevant financial disclosures.