Two previous studies analyzed the association between chemerin and the OGTT-based Matsuda insulin sensitivity index (ISI) [11,26] with contradictory results: the first study in Japanese patients with type 2 diabetes found a significant inverse association after adjustment for age, sex and BMI [11], whereas the inverse association between chemerin and Matsuda ISI in children from Germany was mainly explained by age and BMI [26]. This evidence concerns the gene RARRES2 and type 2 diabetes mellitus.