BMI alone may not be enough to measure cardiometabolic disease risk among adults, UTHealth Houston researchers find

Body mass index (BMI) alone may not be enough to measure someone’s risk of cardiometabolic disease, according to researchers at UTHealth Houston.

The research, led by a team from the Border Health Research Cohort at UTHealth Houston School of Public Health, was published in JAMA Network Open and focused on the relationship between adiposity, or excess fat tissue, and cardiometabolic disease in adults.  

Cardiometabolic disease is a group of health problems like heart disease and diabetes that are often caused by things like being overweight or having high blood pressure or high blood sugar.

“When you have excess adiposity, even if you're not obese, you're still at risk for cardiometabolic disease,” said co-principal investigator Joseph Mccormick, MD, professor of epidemiology and James H. Steele, DVM, Professor at UTHealth Houston School of Public Health. “This adipose tissue is a big driver of the elements that make up what we call cardiometabolic disease.” 

The research was a companion piece to a study published last month in JAMA Pediatrics, which focused on adiposity and obesity in children. 

For adults, a BMI of 30 or greater is typically considered obese. Researchers found that measuring adiposity – specifically, the waist and hips of a patient – in addition to BMI provides a more accurate metric of disease risk. 

"Patients often visit their doctor, get weighed, and are told that with a BMI of 25 or lower they are at very low risk of cardiometabolic disease,” said co-principal investigator Kari North, PhD, director of the Border Health Research Center and professor at the School of Public Health. “However, our findings show that some of these individuals actually have excess adiposity, placing them at significant risk for Type 2 diabetes, high cholesterol, and hypertension.”

To conduct the study, researchers focused on 1,465 adult participants in Cameron County, where the risk of cardiometabolic disease among the adult population is high. Adiposity was analyzed by measuring patients’ waist circumference and comparing it to a metric that is commonly used to measure bone density but can also be used to measure total body fat. 

Researchers found that more than 96% of participants who were considered obese had excess body fat by both metrics. Waist circumference measurements alone revealed that 17% of participants who were not obese had excess adiposity, while the metric focusing on bone density revealed that 58% of participants who were not obese had excess adiposity. 

The team emphasized that for clinicians, measuring adiposity is important in combatting the epidemic of cardiometabolic disease. Men with a waist circumference of 40.1 inches or more and women with a waist circumference with 34.6 inches or more are more likely to have excess adiposity, according to the research. 

“BMI is a very good marker because 98% of the people who have BMIs of 30 or more have excess adiposity. But that's not enough,” Mccormick said. “We already know that the second highest risk of diabetes and cardiovascular disease in adults is related to excess adiposity, particularly around the abdomen.”

The Border Health Research Cohort, founded by McCormick, 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.

Co-principal investigators of the study included Susan Fisher-Hoch, MD, professor of epidemiology at the School of Public Health, and Jennifer E. Below, PhD, of Vanderbilt University. 

Additional co-authors include Alexandra B. Palmer, PhD, and Penny Gordon-Larsen, PhD, of the University of North Carolina at Chapel Hill, and Rashedeh Roshani of Vanderbilt University.