Relative role of insulin resistance and beta-cell dysfunction in the progression to type 2 diabetes--The Kinmen Study

This study compared the relative role of insulin resistance and beta-cell dysfunction (both assessed using the HOMA method) with glucose intolerance conditions in the progression to type 2 diabetes among a high risk group of subjects with fasting plasma glucose (FPG) 5.6-7.0 mmol/l in Kinmen, Taiwan. Data were collected during a continuing prospective study (1998-99) of a group of Taiwanese subjects at high-risk of developing type 2 diabetes who had fasting hyperglycemia (5.6-7.0 mmol/l) and exhibited 2-h postload glucose concentrations <11.1 mmol/l from 1992-94 to 1995-96. Among 644 non-diabetic subjects at baseline, 79.8% (514/644) had at least one follow-up examination. There were 107 new cases of diabetes diagnosed by 1999 WHO criteria in 2918.7 person-years of follow-up. The incidence rate was 3.67%/year (107/2918.7). After adjustment for other possible associative variables, including gender, age, BMI, waist circumference, insulin resistance, and beta-cell dysfunction, Cox's hazard model showed that those individuals with isolated IFG (impaired fasting glucose) and those individuals with isolated IGT (2-h glucose impairment) exhibited similar risk of developing diabetes. Those individuals with isolated IFG and isolated IGT showed a comparable impairment of basal or hepatic insulin sensitivity, but those individuals with isolated IFG had a greater beta-cell dysfunction by the HOMA method.