Higher circulating orosomucoid, an acute-phase protein, and reduced glucose-induced insulin secretion in middle-aged Japanese people with prediabetes

INTRODUCTION: Circulating orosomucoid, an acute-phase protein, predicted type 2 diabetes mellitus risk in several Western countries. Here, we assessed serum orosomucoid (ORM) in relation to prediabetes in the Japanese. RESEARCH DESIGN AND METHODS: Participants consisted of 83 middle-aged Japanese subjects with normal glucose tolerance (NGT), 37 with prediabetes and 4 with newly identified diabetes, whose homeostasis model assessment-insulin resistance (HOMA-IR) averaged 1.1±0.7, 1.4±0.9 and 1.7±0.8, respectively. Body composition, serum inflammatory markers, adiponectin, β-cell function and insulin resistance inferred from serum insulin kinetics during an oral glucose tolerance test were compared cross-sectionally between those with prediabetes and NGT. RESULTS: Serum orosomucoid, but not high-sensitivity C reactive protein, was elevated in prediabetes (190±29 vs 141±31 mg/dL) with further elevation in diabetes (295±52 mg/dL) (all p<0.001). Prediabetes was associated with lower Oral Disposition Index (the product of the Insulinogenic Index and Matsuda Index) with further depression in diabetes. No association was found with skeletal muscle mass, HOMA-IR, serum triglyceride, high-density lipoprotein (HDL) cholesterol and adiponectin. CONCLUSIONS: Higher circulating ORM and reduced glucose induced insulin secretion were found in middle-aged Japanese people with prediabetes in the absence of insulin resistance.