As an epidemiologist, my research is related to childhood obesity and nutrition and their long-term impact on cardiometabolic health into adulthood. I am also interested in early-life exposures occurring during pregnancy and breastfeeding that may help establish developmental trajectories into childhood and beyond. I have significant expertise in how children develop relative to growth charting. My goal is to understand whether there are critical periods in early life or key aspects of developmental exposures that may prevent future obesity and cardiometabolic diseases.

My early research focused on infancy and the role of breastfeeding and human milk composition in modulating obesity risk. This work used a set of parallel international cohorts recruited in Cincinnati, Mexico City and Shanghai. I evaluated the role of human milk adiponectin in infant growth while considering complementary feeding timing and diversity of foods in this relationship.

My groundbreaking work has centered on the use of growth charts to evaluate infant obesity and identify critical time periods for the development of early-onset severe obesity. In 2009, I identified that the Centers for Disease Control and Prevention (CDC) body mass index (BMI) z-scores, used widely in clinical and research applications, have a critical flaw. In particular, because of how they were developed, CDC BMI z-scores do not effectively differentiate the weight status of children and adolescents with severe obesity. This topic was the focus of a National Center for Health Statistics (NCHS) workshop that aimed to propose alternative metrics for effectively assessing adiposity status at the high end of the distribution. This work has resulted in several manuscript publications and altered recommendations for the use of CDC growth charts.

Traditionally, there has not been a definition of obesity for children under the age of two and a hesitancy to identify infants as obese. My studies have identified that children who develop severe early-onset (prior to age 6) obesity have a significantly different BMI trajectory in infancy that is identifiable as early as six months of age. Infants at or above the 85th percentile on the World Health Organization (WHO) BMI growth charts have a 50 percent risk of being overweight or obese by age six, compared with just 11 percent of those below this threshold.