YKL-40 Level Is Associated with TyG-BMI-Estimated Insulin Resistance and Metabolic Syndrome in a Population Without Diabetes, Independent of Obesity

YKL-40, an obesity-related inflammatory biomarker, has inconsistently been associated with insulin resistance, and its relationship with metabolic syndrome is not well established. This study investigated the associations of YKL-40 levels with insulin resistance and metabolic syndrome independently of obesity. We analyzed data from 4303 participants without diabetes in the Taiwan Biobank. Insulin resistance was defined by the highest quartile of triglyceride-glucose body mass index (TyG-BMI). Metabolic syndrome was defined per AHA/NLHBI criteria. Both univariate and multivariate analyses demonstrated significant correlations between YKL-40 levels and TyG-BMI. Participants with higher YKL-40 quartiles exhibited increased odds of TyG-BMI-estimated insulin resistance even after adjusting for established predictors of TyG-BMI, including waist circumference. Similarly, higher YKL-40 quartiles significantly correlated with increased metabolic syndrome prevalence, and this relationship persisted after stratifying participants by weight status (normal weight vs. overweight/obese). Interaction analysis indicated that overweight/obesity individuals consistently had higher metabolic syndrome prevalence than normal-weight counterparts within identical YKL-40 quartiles, though the impact of overweight/obese diminished across rising YKL-40 quartiles (<i>p</i> for interaction = 0.008). Increased YKL-40 levels are significantly associated with TyG-BMI-estimated insulin resistance and metabolic syndrome, independent of obesity. There is a significant interaction between overweight/obese and YKL-40 levels in determining metabolic syndrome prevalence.