FAT-FREE MASS, METABOLICALLY HEALTHY OBESITY, AND TYPE 2 DIABETES IN SEVERELY OBESE ASIAN ADULTS.

Objective: To determine whether fat free mass (FFM) is independently associated with the metabolically healthy obesity (MHO) phenotype, the metabolic syndrome (MS), and type 2 diabetes (T2D) in obese Asian adults.

Methods: Obese patients (body mass index [BMI] ≥25 kg/m) seeking weight management at an academic medical center from 2007 to 2016 were included. FFM was measured by bioelectrical impedance.

Results: Of the 552 patients (67.0% female, median age 40.5 years, median BMI 38.3 kg/m), MHO was present in 19%, MS in 55.4%, and T2D in 32.6%. In multivariate models, higher fat-free mass index (FFMI) was independently associated with the metabolically abnormal obesity (MAO) phenotype, (odds ratio [OR] 1.22, 95% confidence interval [CI] 1.09-1.37), and increased risk of MS (OR 1.12, 95% CI 1.03-1.22) in women but not in men. Older age was independently associated with the MAO phenotype (OR 1.06, 95% CI 1.04-1.09 in women; OR 1.06, 95% CI 1.02-1.09 in men), MS (OR 1.05, 95% CI 1.03-1.06 in women; OR 1.05, 95% CI 1.02-1.07 in men), and T2D (OR 1.07, 95% CI 1.05-1.09 in women; OR 1.06, 95% CI 1.04-1.09 in men). Waist-hip ratio was independently associated with the MAO phenotype in men (OR 1.08, 95% CI 1.01-1.15), while waist circumference was associated with T2D in women (OR 1.03, 95% CI 1.01-1.05).

Conclusion: Older age, central fat distribution, and-in contrast to previous findings-an increase in FFMI among women were independent predictors of adverse metabolic health in this cohort of middle-aged obese Asian adults. Further studies are required to elucidate underlying mechanisms and therapeutic implications of these findings.

Abbreviations: BIA = bioelectrical impedance analysis BMI = body mass index CI = confidence interval DXA = dual-energy X-ray absorptiometry FFM = fat-free mass FFMI = fat-free mass index FM = fat mass HbA1c = glycated hemoglobin A1c MAO = metabolically abnormal obesity MHO = metabolically healthy obesity MS = metabolic syndrome OR = odds ratio T2D = type 2 diabetes WC = waist circumference WHR = waist-hip-ratio.