BMI Alone May Miss Excess Adiposity in Children, UTHealth Houston Study Finds

While body mass index (BMI) is an effective tool for identifying obesity in children, these measurements alone do not always distinguish kids with unhealthy levels of body fat, especially in low-resource communities along the U.S.-Mexico border, according to researchers at UTHealth Houston.

In a study led by Kari North, PhD, professor of epidemiology and vice president of Border Health at UTHealth Houston School of Public Health in Brownsville, researchers analyzed data from nearly 200 Hispanic children ages 8–17 from the Cameron County Hispanic Cohort (CCHC), a community-based group of more than 5,000 individuals who live along the border from Brownsville to Laredo. For more than 20 years, the cohort has voluntarily provided valuable health data, allowing researchers to study chronic illnesses and health conditions specific to border communities. Researchers compared their results to data from the National Health and Nutrition Examination Survey and found that almost all children classified as obese by BMI also had excess body fat, confirming BMI’s usefulness in detecting obesity. Additionally, nearly one-third of children who were not classified as obese by BMI nonetheless had excess body fat, placing them at higher risk for diabetes, heart disease, and other chronic conditions.

“While BMI is the most common tool for identifying childhood obesity, our new research study shows it overlooks nearly one-third of kids with unhealthy levels of body fat, especially in high-risk communities along the U.S.–Mexico border, underscoring the need for improved obesity screening in children,” said North, co-senior author of the study. “Our findings emphasize the urgent need for improved early detection strategies in high-risk pediatric populations, given high excess adiposity in youth with and without obesity.”

The study also found that simple waist-to-height measurements were nearly as effective as advanced a body scan using dual-energy X-ray absorptiometry (DXA), an X-ray technique that measures body composition including bone density, fat, and lean mass.

The collaborative effort included Joyce Samuel, MD, and Kyung Hyun Lee, PhD, from McGovern School at UTHealth Houston; Alexandra Palmer, PhD, and Rashedeh Roshani, MS, from Vanderbilt University Medical Center; Penny Gordon-Larsen, PhD, Kristin Young, PhD, Mariaelisa Graff, PhD, and Mohammed Anwar, PhD, from University of North Carolina Gillings School of Public Health.

The CCHC, founded by Joseph McCormick, MD, and Susan Fisher-Hoch, MD, professors of epidemiology at UTHealth Houston School of Public Health in Brownsville, is one of the largest and longest-running studies of Mexican-American health in the U.S. It has provided critical insights into the high burden of diabetes, obesity, and related conditions in border communities. By using CCHC data, researchers were able to highlight how pediatric obesity screening tools perform in populations most affected by these diseases.

Fellow co-senior author Jennifer Below, PhD, professor of medicine and director of the Vanderbilt Genetics Institute at Vanderbilt University Medical Center, and co-director of CCHC, noted the importance of this research, “Our study emphasizes the need for improved early detection of excess body fat in children, particularly in communities with high rates of obesity-related illnesses. Early identification could allow for timely interventions to prevent lifelong health problems.”