This is contrary to the findings of Catalán et al. [15], where the study population of obese patients with type 2 diabetes and obese subjects with NGT had a BMI similar to our study subjects (type 2 diabetes 47.0 ± 2.4 (SEM) kg/m2; NGT 44.0 ± 1.3 (SEM) kg/m2), but where the presurgical YKL-40 levels differed significantly between the groups. Here, CHI3L1 is linked to type 2 diabetes mellitus.