Response: Association of Body Mass Index-Adjusted Body Cell Mass and Lean Body Mass with Metabolic Syndrome and Insulin Resistance in Middle-Aged and Older Adults: A Cross-Sectional Study (J Obes Metab Syndr 2026;35:61-71)

We recently reported associations of body mass index (BMI)-adjusted body cell mass (BCMbmi) and BMI-adjusted lean body mass (LBMbmi) with metabolic markers, metabolic syndrome (MetS), and insulin resistance (IR) in middle-aged and older Korean adults. 1 In the accompanying Letter, the author raised two important methodological considerations: the potential influence of the denominator on associations involving BCMbmi and the interpretation of differences between BCMbmi and LBMbmi.We thank the author for the opportunity to examine and clarify these issues.First, we agree that associations involving a ratio-based measure may be influenced by its denominator.2 To assess this possibility, we conducted additional sex-stratified sensitivity analyses that included absolute BCM and BMI simultaneously as separate continuous variables.BCM and BMI were standardized within each sex.The models were adjusted for age, smoking status, alcohol consumption, regular exercise, household income, and marital status.Body weight was excluded because BMI was already included in the models.After accounting for BMI, absolute BCM was not inversely associated with MetS or IR (Table 1).Among men, each one-standarddeviation increase in absolute BCM was associated with an odds ratio (OR) of 1.12 for MetS (95% confidence interval [CI], 1.02 to 1.23; P= 0.017) and 0.94 for IR (95% CI, 0.85 to 1.02; P= 0.148).Among women, the corresponding ORs were 1.21 for MetS (95% CI, 1.12 to 1.31; P< 0.001) and 1.12 for IR (95% CI, 1.03 to 1.21; P= 0.005).These findings show that the inverse associations observed for BCMbmi did not persist when absolute BCM and BMI were modeled separately.Therefore, our original findings should not be interpreted as evidence that greater absolute BCM was independently associated with lower odds of MetS or IR.BCMbmi is better interpreted as a relative body-composition index reflecting BCM in relation to BMI.Properties related to the denominator may have influenced the direction and magnitude of the observed associations.Second, we agree that small differences in the area under the receiver operating characteristic curve do not necessarily indicate bi-