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Aims: We compared 20 previously reported indices of insulin sensitivity derived from samples during an oral glucose tolerance test (OGTT) to determine which was best in predicting incident type 2 diabetes., Methods: We prospectively followed 418 Japanese Americans without diabetes for 10-11 years. We compared ability to predict incident diabetes of 20 insulin sensitivity indices-9 based on fasting samples, 7 based on 2-h and/or fasting samples, and 4 based on multiple samples (0, 30, 60, 120 min) during an OGTT-by integrated discrimination improvement, category free net reclassification improvement, and area under the receiver operator characteristic curve., Results: There were 95 incident cases of diabetes. The Cederholm and Gutt indices, requiring more than only fasting samples, were the best to predict incident diabetes as judged by integrated discrimination improvement (0.187, 0.184), category free net reclassification improvement (0.962, 1.030), and area under the receiver operator characteristic curve (0.864, 0.863, respectively). Fasting indices were clearly inferior to both the Cederholm and Gutt indices., Conclusions: Among the 20 indices, the Cederholm and Gutt indices predicted diabetes best but the Gutt index may be preferable because it requires fewer samples during an OGTT., Competing Interests: Declaration of competing interest No author reports potential conflicts of interest or competing financial interests or personal relationships that could have appeared to influence the work reported in the paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Aims: We examined the longitudinal association between change in body composition directly measured by computed tomography (CT) and future insulin sensitivity., Methods: This was a prospective study with 10 years of follow-up with 297 Japanese-American without diabetes. Intra-abdominal fat area (IAFA) and abdominal subcutaneous fat area (SCFA), and thigh SCFA were measured by CT. Insulin sensitivity was calculated by HOMA-IR and the Matsuda index., Results: Baseline and change in IAFA were significantly and independently associated with change in HOMA-IR and Matsuda index during follow-up. In multivariate analysis, IAFA and 10-year change in IAFA (Δ IAFA) was significantly and positively associated with 10-year HOMA-IR (p < 0.001) and significantly and negatively associated with 10-year Matsuda index (p < 0.001). The association with Matsuda index though was non-linear and best modeled as a quadratic function (Δ IAFA + Δ IAFA 2 ). No significant associations in multivariate analyses were seen between thigh SCFA and insulin sensitivity or abdominal SCFA and HOMA-IR but an increase in abdominal SCFA was associated with diminished insulin sensitivity measured by the Matsuda index., Conclusions: An increase in visceral adiposity predicts diminished insulin sensitivity over 10 years of follow-up independent of the size of this adipose depot at baseline., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Aims: To describe the roles of intra-abdominal fat and its change in the remission of impaired glucose tolerance (IGT) to normal glucose tolerance (NGT)., Methods: We followed 157 Japanese Americans with IGT at baseline for 10-11 years without external intervention. We measured intra-abdominal and abdominal subcutaneous fat area (IAFA and ASFA) by computed tomography at baseline and at 5-6 years of follow-up. Change in IAFA and ASFA (ΔIAFA and ΔASFA) were calculated by subtracting baseline fat area from 5-6 year follow-up fat area. Glucose and insulin at fasting and during a 75-g oral glucose tolerance test, insulinogenic index (IGI [Δinsulin/Δglucose (30-0 min)]) and homeostasis model assessment for insulin resistance (HOMA-IR) were measured at baseline., Results: Fourty-four subjects remitted to NGT. Among those with lower IAFA (≤median 91.31 cm 2 ) and the lowest tertile of ΔIAFA, 45% remitted, while with higher IAFA (>91.31 cm 2 ) and the highest tertile of ΔIAFA, only 12.5% remitted. ΔIAFA was significantly associated with remission to NGT (multiple-adjusted odd ratio [1-SD decrease] 1.93, 95% CI 1.10-3.36) independent of IAFA, ASFA, ΔASFA, IGI, HOMA-IR, age, sex, and family history of diabetes., Conclusions: In the natural history of IGT, change in intra-abdominal fat was associated with remission to NGT., (Copyright © 2018. Published by Elsevier B.V.)