Journal of Diabetes Research (Jan 2016)

Insulin Secretory Defect and Insulin Resistance in Isolated Impaired Fasting Glucose and Isolated Impaired Glucose Tolerance

  • Sae Aoyama-Sasabe,
  • Mitsuo Fukushima,
  • Xin Xin,
  • Ataru Taniguchi,
  • Yoshikatsu Nakai,
  • Rie Mitsui,
  • Yoshitaka Takahashi,
  • Hideaki Tsuji,
  • Daisuke Yabe,
  • Koichiro Yasuda,
  • Takeshi Kurose,
  • Nobuya Inagaki,
  • Yutaka Seino

DOI
https://doi.org/10.1155/2016/1298601
Journal volume & issue
Vol. 2016

Abstract

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Objective. To investigate the characteristics of isolated impaired glucose tolerance (IGT) and isolated impaired fasting glucose (IFG), we analyzed the factors responsible for elevation of 2-hour postchallenge plasma glucose (2 h PG) and fasting plasma glucose (FPG) levels. Methods. We investigated the relationship between 2 h PG and FPG levels who underwent 75 g OGTT in 5620 Japanese subjects at initial examination for medical check-up. We compared clinical characteristics between isolated IGT and isolated IFG and analyzed the relationships of 2 h PG and FPG with clinical characteristics, the indices of insulin secretory capacity, and insulin sensitivity. Results. In a comparison between isolated IGT and isolated IFG, insulinogenic index was lower in isolated IGT than that of isolated IFG (0.43 ± 0.34 versus 0.50 ± 0.47, resp.; p<0.01). ISI composite was lower in isolated IFG than that of isolated IGT (6.87 ± 3.38 versus 7.98 ± 4.03, resp.; p<0.0001). In isolated IGT group, insulinogenic index showed a significant correlation with 2 h PG (r=-0.245, p<0.0001) and had the strongest correlation with 2 h PG (β=-0.290). In isolated IFG group, ISI composite showed a significant correlation with FPG (r=-0.162, p<0.0001) and had the strongest correlation with FPG (β=-0.214). Conclusions. We have elucidated that decreased early-phase insulin secretion is the most important factor responsible for elevation of 2 h PG levels in isolated IGT subjects, and decreased insulin sensitivity is the most important factor responsible for elevation of FPG levels in isolated IFG subjects.