The effect of infant feeding on childhood body composition

Abstract

Childhood overweight and obesity has been increasing in the United States. According to the 2009-2010 National Health and Nutrition Examination Survey (NHANES), almost one third of children and adolescents in America are either overweight or obese. Overweight is defined as at or above the 85th percentile and less than the 95th percentile on the Center for Disease Control and prevention (CDC) BMI-for-age growth charts. Obesity is defined as at or above the 95th percentile on the CDC BMI-for-age growth charts. With increasing childhood weight there is an increased risk in health related issues. The use of infant formula has been thought to increase the risk of childhood obesity, but research is inconclusive to whether infant feeding practices are related to childhood body composition. Studies have found that breast feeding may have protective effect again childhood overweight and underweight, but there are other factors such as maternal weight status, ethnicity, and lifestyle habits that may confound these results. Other studies have shown differences in infant weight status for those who are fed formula versus breast milk, but these differences are not seen after one year of age. The purpose of this study is to determine if there is a relationship between infant feeding practices and childhood body composition and anthropometrics. Infant feeding practices for this study includes a) exclusively breast fed, b) bottle fed with expressed breast milk, c) exclusively formula fed and d) mixed feeding with formula and human milk. Most research does not include human milk fed by bottle or take into account mixed feeding practices. Some of the published reports use childhood anthropometrics as a surrogate marker of adiposity instead of measuring actual fat mass and fat free mass. This study includes childhood anthropometrics (BMI-for-age percentiles) and body composition (fat mass, fat free mass and percent body fat). We used multiple linear regression data analysis to assess the relationship between infant feeding practices and each of the body composition and anthropometric measurements (fat mass, fat free mass, percent body fat, and BMI-for-age percentile at three, four and five years old). We used a stepwise process to remove maternal confounding variables (maternal PPVT, race, smoking status, long chain polyunsaturated fatty acid supplementation during pregnancy and pre-pregnancy BMI) that had a change in significance of greater than 0.1 on the variability of the childhood body composition and anthropometric measurement. In the final model, we found no significant relationships between infant feeding practices at four months old and childhood body composition at five years of age and anthropometrics at three, four and five years old. This study has similarities with the recent research showing no difference between infant feeding practices on childhood body composition and anthropometrics. Although, there have been a few studies showing positive relationships between infant feeding practices and childhood weight status. These studies also determined that maternal characteristics confound or influence these findings, indicating there are other factors involved with childhood overweight and obesity. Childhood overweight and obesity may be influenced more by parental genetic factors or by childhood activity and dietary habits than infant feeding practices.