Tohoku J. Exp. Med., 2007, 212(4)

Impaired Glucose Tolerance and Impaired Fasting Glucose Share Similar Underlying Pathophysiologies

JIUNN DIANN LIN,¹ HSIANG-LIN WAN,¹ JER-CHUAN LI,² CHUNG-ZE WU,³ SHI-WEN KUO,¹ CHANG-HSUN HSIEH,³ WEI-CHEN LIAN,⁴ CHIEN-HSING LEE,³ MEI-TENG KAO⁵ and DEE PEI¹

¹Department of Medicine, Division of Endocrinology and Metabolism, Buddhist Tzu Chi General Hospital and College of Medicine, Tzu Chi University, Taipei, Taiwan
²Department of Medicine, Division of Endocrinology and Metabolism, Buddhist Tzu Chi General Hospital and College of Medicine, Tzu Chi University, Hualien, Taiwan
³Department of Internal Medicine, Tri-Service General Hospital, Taipei, Taiwan
⁴Department of Medicine, Division of Endocrinology and Metabolism, Buddhist Tzu Chi General Hospital and College of Medicine, Tzu Chi University, Da-Lin, Taiwan
⁵Department of Internal Medicine, Tzu-Ai General Hospital, Yunlin, Taiwan

Both impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) are pre-diabetic states. IGT was defined as having normal fasting plasma glucose (< 6.1 mmol/l) and abnormal 2-hr post-challenge plasma glucose. IFG was defined as having abnormal fasting plasma and normal 2-hr post-challenge plasma glucose (< 7.8 mmol/l). To explore whether these two abnormalities share similar underlying pathophysiologies, we evaluated risk factors of IGT and IFT using the models of factor analysis. The present study included 107 subjects with IGT and 52 with IFG. An oral glucose tolerance test and insulin suppression test, which could quantify insulin resistance, were performed on separate days. The risk factors include waist-to-hip ratio (WHR), triglycerides, high-density lipoprotein (HDL)-cholesterol, blood pressure, and fasting plasma glucose, which are associated with metabolic syndrome and insulin resistance. Factor analysis is a commonly used statistical method that could reduce a large number of risk factors into smaller numbers of groups, also called dimension. Accordingly, the complicated data could be interpreted more easily, since the related risk factors are grouped in one dimension. The results showed that the risk factors of IGT and IFG have similar grouping patterns. Triglyceride, insulin resistance, and HDL-cholesterol were grouped in one dimension (the lipid dimension), while WHR, mean blood pressure and fasting plasma glucose were grouped in another dimension (the metabolic dimension). In conclusion, except for WHR, the grouping patterns of the components in both IGT and IFG were nearly identical. These results suggest that IGT and IFG may share similar pathophysiologies.

keywords —— factor analysis; metabolic syndrome; insulin resistance; impaired glucose tolerance; impaired fasting glucose

© 2007 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2007, 212, 349-357

Present address: Dee Pei, M.D., Floor 31, No 40, Huanhe Rd, Xindian City, Taipei County, Taiwan, R.O.C.
Correspondence: Dee Pei, M.D., Department of Internal Medicine, Cardinal Tien Hospital, No 362, Chung Cheng Rd., Hsintien Taipei Hsien 23137, Taiwan, R.O.C.

e-mail: peidee@gmail.com