Factors Responsible for Development From Normal Glucose Tolerance to Isolated Postchallenge Hyperglycemia
- Haruhiko Suzuki, MD, MPH1,
- Mitsuo Fukushima, MD, PHD1,
- Masaru Usami, MD, PHD2,
- Masaki Ikeda, MD, PHD2,
- Ataru Taniguchi, MD, PHD3,
- Yosikatsu Nakai, MD, PHD4,
- Toshifumi Matsuura, MD5,
- Akira Kuroe, MD, PHD1,
- Koichiro Yasuda, MD, PHD1,
- Takeshi Kurose, MD, PHD1,
- Yutaka Seino, MD, PHD1 and
- Yuichiro Yamada, MD, PHD1
- 1Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- 2Ikeda Hospital, Hyogo, Japan
- 3Kansai-Denryoku Hospital, Osaka, Japan
- 4College of Medical Technology, Kyoto University, Kyoto, Japan
- 5Kansai Health Management Center, Osaka, Japan
Abstract
OBJECTIVE—Isolated postchallenge hyperglycemia (IPH), defined as fasting plasma glucose (FPG) level <7.0 mmol/l and 2-h plasma glucose (PG) level ≥11.1 mmol/l, is a subtype of early-stage diabetes. This study evaluates the metabolic profiles of insulin secretion and insulin sensitivity in IPH to clarify the factors responsible for development of this form of type 2 diabetes.
RESEARCH DESIGN AND METHODS—We conducted cross-sectional analysis of 231 Japanese men aged 20–70 years. The subjects were classified into the following three groups, based on the results of a 75-g oral glucose tolerance test (OGTT): 1) normal glucose tolerance (NGT), defined as FPG level <6.1 mmol/l and 2-h PG level <7.8 mmol/l (n = 89); 2) impaired glucose tolerance (IGT), defined as FPG level <7.0 mmol/l and 2-h PG level of 7.8–11.1 mmol/l (n = 94); and 3) IPH (n = 48). We compared the three groups for insulin secretion (insulinogenic index) and insulin sensitivity (index of insulin resistance using homeostasis model assessment [HOMA-IR]).
RESULTS—The insulinogenic index in IPH was the lowest of the three groups (P < 0.001 versus NGT). The HOMA-IR in the IGT and IPH groups were significantly higher than in the NGT group (P < 0.001), but both were similar. By linear regression analysis, the insulinogenic index rather than fasting insulin or HOMA-IR was the more significant factor in the 2-h PG level in IGT and IPH.
CONCLUSIONS—Subjects with IPH exhibited distinctly impaired early-phase insulin secretion and only mild insulin resistance, indicating that reduced insulin secretion is the primary determinant of deterioration from NGT to IGT and IPH in development of type 2 diabetes in these subjects.
- FPG, fasting plasma glucose
- HOMA-IR, index of insulin resistance using homeostasis model assessment
- IGT, impaired glucose tolerance
- IGT/FH, IGT with fasting hyperglycemia
- IPH, isolated postchallenge hyperglycemia
- ISI, insulin sensitivity index
- NGT, normal glucose tolerance
- OGTT, oral glucose tolerance test
- PG, plasma glucose
Footnotes
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Address correspondence and reprint requests to Mitsuo Fukushima, MD, PhD, Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, 54 Kawaharacho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. E-mail: fukusima{at}metab.kuhp.kyoto-u.ac.jp.
Received for publication 13 August 2002 and accepted in revised form 23 December 2002.
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