Hyperinsulinemia and Related Atherosclerotic Risk Factors in the Population at Cardiovascular Risk: A Community-based Study Kuo-Liong Chien, 1 Yuan-Teh Lee, 1* Fung-Chang Sung, 2 Hsiu-Ching Hsu, 1 Ta-Chen Su, 1 and Ruey S. Lin 3 Background: A population-based study was conducted in Taiwan to investigate the prevalence of insulin resis- tance and high serum insulin concentrations and their relationships with potential atherosclerotic risk factors. Methods: We studied 2165 subjects, ages >35, from a community cohort. Results: The distributions of fasting insulin were skewed to the right, with higher concentrations in women than in men. As age increased, insulin increased in women, but decreased in men. As fasting insulin concentrations increased, postloading insulin, glucose, blood pressure, body mass index, waist-to-hip ratio, total cholesterol, triglycerides, LDL-cholesterol, apopro- tein B, plasminogen activator inhibitor 1, tissue plas- minogen activator, and fibrinogen increased, but li- poprotein(a), HDL-cholesterol, and apoprotein A1 decreased. Multiple logistic regression showed that obe- sity, high LDL-cholesterol, and low HDL-cholesterol were significant predictors of hyperinsulinemic status. Conclusion: The study subjects with insulin resistance syndrome and related risk factors may be at risk for atherosclerosis, thrombosis, and other coronary heart diseases. © 1999 American Association for Clinical Chemistry Hyperinsulinemia has been identified as a risk factor for hypertension and obesity as well as lipid abnormalities in adults (1–3 ). Prospective studies have also demonstrated that high plasma concentrations of insulin predict the development of coronary heart disease (CHD), 4 indepen- dent of other risk factors (1–3 ). Hyperinsulinemia, which leads to a cluster of cardiovascular risks, is well known as “insulin resistance syndrome” (4, 5) and is strongly re- lated to abnormalities of carbohydrate metabolism (6, 7). Some studies have addressed racial differences in the clustering of insulin resistance syndrome, including hy- pertension, obesity, dyslipidemia, and hyperinsulinemia (8). Environmental studies showed marked differences in CHD mortality rates among countries and relative im- pacts on atherosclerosis among populations. Racial dis- crepancies have also been reported for diabetes mellitus and insulin concentrations (9). Pima Americans, aborigi- nal Australians, and South Asians have relatively higher prevalences of diabetes than Caucasians (10 –12 ). Com- mon to most of these groups are a recent trend toward urbanization, a decrease in physical activity, and the development of obesity. Populations with high incidence rates for CHD are also at high risk for diabetes (11 ), which may be related to insulin resistance. One population-based study has dem- onstrated that fasting insulin concentrations were lower in the Japanese than in Caucasians (9). The distribution patterns of atherosclerotic risk factors between these two ethnic groups were also different. For the Chinese population, the distribution of fasting insulin in the general population has not yet been ad- dressed. Moreover, the relationships between insulin con- centration, blood pressure, lipid concentrations, and co- agulation factors in Chinese remain to be explored. A recent study in Mauritius found that both fasting and 2-h 1 Department of Internal Medicine, National Taiwan University Hospital, 7 Chung Shan South Rd., Taipei, Taiwan 10016. Institutes of 2 Environmental Health and 3 Epidemiology, National Taiwan University College of Public Health, Taipei, Taiwan 100. *Author for correspondence. Fax 886-2-2395-9911; e-mail ytlee@ ha.mc.ntu.edu.tw. Received September 16, 1998; accepted March 18, 1999. 4 Nonstandard abbreviations: CHD, coronary heart disease; CCCC, the Chin-Shan Community Cardiovascular Cohort; BMI, body mass index; WHR, waist-to-hip ratio; LDL-C, LDL-cholesterol; HDL-C, HDL-cholesterol; apo A1, apoprotein A1; apo B, apoprotein B; Lp(a), lipoprotein(a); tPA, tissue plasmin- ogen activator; PAI-1, plasminogen activator inhibitor; and HOMA, homeosta- sis model assessment. Clinical Chemistry 45:6 838 – 846 (1999) Endocrinology and Metabolism 838