RISK-FACTORS FOR THE DEVELOPMENT OF NIDDM IN YONCHON COUNTY, KOREA

OBJECTIVE - To determine the risk factors for the development of NIDDM in Yonchon County of Korea. RESEARCH DESIGN AND METHODS - We studied 1,193 Korean nondiabetic subjects at baseline who participated in a 2- year follow-up study on diabetes in Yonchon County. A 75-g oral glucos e tolerance test was performed 2 years after the baseline examination. Age, sex, and anthropometric and metabolic characteristics at baselin e were analyzed simultaneously as potential predictors of conversion t o NIDDM. We also designed a nested case-control study to determine the role of hyperinsulinemia and/or hyperproinsulinemia in the conversion to NIDDM in patients with newly developed diabetes and control subjec ts matched for age, sex, BMI, and waist-to-hip-ratio. RESULTS - At 2 y ears, 67 subjects developed diabetes, as defined by World Health Organ ization criteria. The age-adjusted incidence was significantly higher in men (6.4%) than in women (3.0%), and the incidence increased as age increased in both sexes. Multiple logistic regression analysis reveal ed age, male sex, and fasting and 2-h glucose levels to be significant risk factors for the development of NIDDM, whereas waist-to-hip ratio and BMI were not. In a nested case-control study baseline proinsulin but not insulin levels were significantly higher in subjects who progr essed to NIDDM than in those who did not. CONCLUSIONS - In the Korean population, beta-cell dysfunction, as measured by high proinsulin leve ls, seems to be associated with subsequent development of NIDDM, where as regional and general obesity and fasting insulin levels, which may be a surrogate for insulin resistance, were not.