chen, zhuo

Background: The role of body adiposity on metabolic dysregulation in subjects with normal body mass index (BMI) is still under debate with limited population-based evidence. Hypothesis: Body adiposity measured by dual x-ray absorptiometry (DEXA) is associated with metabolic disorders in normal-weight individuals. Methods: We evaluated a sample of adults aged 20-65 who underwent DEXA in the US National Health and Nutrition Examination Surveys from 1999-2006 and 2011-2018. We excluded those with history of cardiovascular disease, cancer, and chronic obstructive pulmonary disease. Weighted logistic regression was performed to test the association between body fat percentage (BF%) and metabolic disorders [e.g., insulin resistance (IR), metabolic syndrome (MS), dyslipidemia, type 2 diabetes mellitus (DM), hypertension]. Models were adjusted for potential confounders while considering complex survey design and were further stratified by sex and BF% as tertiles in normal-weight individuals. IR was tested as a secondary analysis to evaluate the effect on the predicted risk. Results: We included 20,613 individuals (51.5% men, 65.4% non-Hispanic whites), mean age ± SE was 39.42±0.22 years, and 6,424 were normal weight by BMI and represented our study sample. The overall BF% in these subjects measured by DEXA was 28.41±0.19%. In our cohort, metabolic disorders were prevalent in 2.1% to 40.4% of patients (Table 1). Every 10-unit % increase in total BF% was associated with a higher risk for IR, MS, dyslipidemia in the normal weight BMI group (Table 1). Metabolic disorders were associated with BF% tertiles (Figure 1). IR was significantly associated with body fat across all BF% tertiles for men and highest tertiles for women (Figure 2). Conclusion(s): Less than 1/3 of subjects in a representative national sample had a normal BMI. Even in these “normal weight” subjects, increases in body adiposity are significantly associated with increased cardiometabolic disease burden.