Association of Total Body Fat Percentiles, Obesity and Cardiometabolic Health Biomarkers in Adults in the United States.

OBJECTIVE

To estimate total body fat percentage (TBFP) percentiles and their association with obesity and cardiometabolic risk biomarkers in the United States adult population.

METHODS

Cross-sectional data for adults (20-59 years) from the 2011-2018 National Health and Nutrition Examination Survey (NHANES) were analyzed (N = 14,347). TBFP was assessed using dual-energy X-ray absorptiometry. TBFP percentiles were calculated using age-adjusted, weighted quantile regression. Receiver operating characteristic (ROC) analyses assessed the ability of TBFP to predict obesity (body mass index [BMI] ≥ 30 kg/m2), elevated HbA1c (≥ 5.7%), and alanine aminotransferase (ALT) thresholds (≥ 20 and ≥ 40 U/L); and the ability of BMI to predict elevated TBFP.

RESULTS

TBFP percentiles were similar across groups, but non-Hispanic Black men had significantly lower odds of TBFP ≥ 90th percentile compared with non-Hispanic White men. TBFP demonstrated accuracy in predicting BMI-defined obesity (AUC 0.83-0.91), and BMI demonstrated accuracy in predicting elevated TBFP (AUC 0.80-0.90). TBFP had limited ability to predict elevated HbA1c (AUC 0.52-0.65) and ALT (AUC 0.51-0.63).

CONCLUSIONS

TBFP percentiles are associated with BMI-defined obesity but are insufficient to predict cardiometabolic risk independently. These findings support the continued use of BMI as a screening tool and suggest that TBFP may complement but not replace existing measures.