Impaired peripheral insulin sensitivity in non‐obese Japanese patients with type 2 diabetes mellitus and fatty liver

AIMS/INTRODUCTION: Type two diabetes mellitus and fatty liver (FL) are not uncommon in Asians with normal body mass index. Previous studies reported a link between FL and insulin resistance. Thus, FL could coexist with insulin resistance in Asian type two diabetes mellitus patients with a normal body mass index. However, the clinical and metabolic features of such patients have not been characterized yet. MATERIALS AND METHODS: We recruited 29 non‐obese (body mass index <25 kg/m(2)) Japanese patients with early type two diabetes mellitus. Based on intrahepatic lipid level measured by H‐magnetic resonance spectroscopy, the participants were divided into the FL (intrahepatic lipid ≥5%, n = 7) and non‐FL groups (intrahepatic lipid <5%, n = 22). RESULTS: Peripheral insulin sensitivity measured by hyperinsulinemic euglycemic clamp was ~25% lower in the FL group than in the non‐FL group, whereas hepatic insulin sensitivity was comparable between the two groups. The subcutaneous fat area was larger, free fatty acid level was higher, C‐reactive protein was higher and high molecular weight adiponectin was lower in the FL group than the non‐FL group. CONCLUSIONS: The present study showed that the metabolic features of non‐obese Japanese type two diabetes patients with FL include impaired peripheral (mainly muscle) insulin sensitivity, fat accumulation and related metabolic disorders, such as elevated free fatty acid, low high molecular weight adiponectin and low‐grade inflammation.