Impaired β-cell function and insulin sensitivity in Japanese subjects with normal glucose tolerance

• Published in: Diabetes research and clinical practice Vol. 59; no. 1; pp. 71 - 77
• Main Authors: Kuroe, Akira, Fukushima, Mitsuo, Usami, Masaru, Ikeda, Masaki, Nakai, Yoshikatsu, Taniguchi, Ataru, Matsuura, Toshifumi, Suzuki, Haruhiko, Kurose, Takeshi, Yasuda, Koichiro, Yamada, Yuichiro, Seino, Yutaka
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 2003; Elsevier Science
• Subjects: Adult; Asian Continental Ancestry Group; Biological and medical sciences; Blood Glucose - analysis; Body Mass Index; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Fasting - blood; Glucose - metabolism; Glucose Tolerance Test; HOMA β-cell; HOMA-IR; Homeostasis; Humans; Insulin Resistance; Insulinogenic index; ISI composite; Islets of Langerhans - pathology; Islets of Langerhans - physiopathology; Japan; Medical sciences; Middle Aged; Asia; Japan; HOMA-IR; ISI composite; HOMA β-cell; Insulinogenic index; Endocrinopathy; Human; Pancreatic hormone; Glucose tolerance test; Non insulin dependent diabetes; Insulin; Endocrine secretion; Protein hormone; Body mass index; Target tissue resistance; Sensitivity; Langerhans cell; Euglycemia; Age
• ISSN: 0168-8227; 1872-8227
• DOI: 10.1016/S0168-8227(02)00177-8

The development of type 2 diabetes mellitus is characterized by both impaired β-cell function and increasing insulin resistance. To clarify the roles of them in developing type 2 diabetes, we evaluated insulin resistance by HOMA-IR and insulin secretion by HOMA β-cell in 453 Japanese subjects whose fasting plasma glucose (FPG) and HbA 1c levels were within normal range. HOMA β-cell was found to decrease in the over 30 years groups, while HOMA-IR increased with body mass index (BMI). To analyze the reserve capacity of insulin secretion and insulin sensitivity, the 67 of them, who underwent a standard oral glucose tolerance test and were diagnosed with normal glucose tolerance (NGT), were divided into four degrees of BMI age-adjusted to 50 years. They were compared for insulinogenic index and ISI composite proposed by Matsuda and DeFronzo across the range of BMI. ISI composite was significantly less in the highest BMI group, while insulin secretion did not increase in the higher BMI groups. The subjects with higher BMI had remarkably lower insulinogenic indices than those with lower BMI. These data suggest that insulin secretory reserve is insufficient to compensate for increased insulin resistance in Japanese people with NGT at about 50 years of age.