A study conducted by researchers at The Children’s Hospital of Philadelphia and Perelman School of Medicine at the University of Pennsylvania revealed that the body mass index (BMI) in infants can be a predictor of obesity at the age of four. The study was published in the Journal of Clinical Endocrinology and Metabolism and is entitled “Body Mass Index (BMI) Trajectories in Infancy Differ by Population Ancestry and May Presage Disparities in Early Childhood Obesity.”
In this study, researchers assessed the relationship between infancy BMI and childhood obesity by analyzing a diverse cohort of children. The BMI corresponds to an approximation of the body fat content, taking into account the height and weight of the individual. After birth, the BMI value increases and reaches a peak during infancy, normally between 8 and 9 months of age.
“Given the public health importance of obesity-related medical problems, we investigated whether BMI in infants could be used as a tool to identify children at increased risk of future obesity, in order to develop better prevention strategies,” said the study’s senior author Dr. Shana E. McCormack in a news release. “We also analyzed ancestry-based differences in growth patterns, and found differences that were apparent at as early as nine months of age were ultimately related to childhood obesity risk.”
The electronic health records of 2,114 healthy infants from The Children’s Hospital of Philadelphia were analyzed. 61% of the children were African-American, a population that is estimated to have the highest rates of diabetes and obesity among American adult individuals.
Researchers found significant differences concerning growth between African-American and white infants primarily of European ancestry. The peak BMI observed in infancy occurred earlier (approximately 12 days) in African-American infants and was around 3% higher in terms of magnitude in comparison with other infants in the cohort. African-American infants exhibited more than twice the risk of obesity at age four in comparison with children who were in their majority of European ancestry.
When interpreting the results based on factors such as the birth weight and socioeconomic status, the researchers found that infancy BMI was a factor more important for determining the risk of childhood obesity than children ancestry. Socioeconomic factors, assessed by insurance and geographic data, were also found to play a role in defining infancy BMI, where an earlier and higher peak BMI was associated with higher rates of poverty.
The reasons why African-American children are at higher risk of childhood obesity are not clear. Researchers plan to assess in future studies the hormone levels in this population, along with the intestinal bacteria and feeding practices (including breastfeeding and formula feeding) and how they affect children’s growth and excess weight gain.
The definition of obesity is, however, not well-defined in children under the age of two. “In the absence of an accepted, valid definition of obesity in infancy, we struggle both as researchers and clinicians with how to best individualize recommendations for infants to prevent childhood obesity. Our findings suggest that infant BMI pattern could be one additional tool. In addition, infant BMI may be an early metric to use in evaluating the impact of public policy interventions,” concluded Dr. McCormack. The research team believes that a better comprehension of the infant growth patterns can be useful in the development of early effective efforts and targeted interventions to prevent obesity.