Best surrogate marker for insulin resistance in middle aged non-diabetic Korean: Chungju metabolic syndrome study

Kim, Ji Hyun; Kwon, Hyuk Sang; Park, Yong Moon; Lim, Sun Young; Lee, Jin Hee; Lee, Seung Hwan; Lim, Dong Joon; Hong, Soon Hwa; Cho, Jae Hyoung; Kim, Sung Rae; Kim, Dong Suk; Yoon, Kun Ho; Lee, Won Chul; Cha, Bong Yun; Lee, Kwang Woo; Kang, Sung Koo; Son, Ho Young

Abstract

BACKGROUND: To investigate the best surrogate marker for insulin resistance in the non-diabetic middle-aged population in Korea.
METHODS
This study was performed from February to April 2003-2005 in adults over 40 years of age living in Chungju City, South Korea, selected by stratified random cluster sampling. We analyzed the data from a total 6,149 non-diabetic subjects that completed a survey consisting of anthropometric measurement and blood chemistry. We defined the highest quartile of the homeostasis model for insulin resistance (HOMA-IR) as the insulin resistant group in our study population. We also analyzed the correlation of various anthropometric (body mass index, waist circumference, waist to hip ratio, waist to height ratio) and biochemical parameters (total cholesterol to HDL cholesterol ratio, non-HDL cholesterol level, triglycerides to HDL cholesterol ratio and level of triglycerides) with insulin resistance using simple and multiple regression analysis for detecting the insulin resistance group.
RESULTS
By simple regression analysis, among the anthropometric parameters including the body mass index, waist circumference, waist to hip ratio, waist to height ratio, and the biochemical parameters, including the total cholesterol to HDL cholesterol ratio, non-HDL cholesterol level, triglyceride to HDL cholesterol ratio and triglycerides level, the body mass index was the best surrogate marker for insulin resistance (95% CI 1.215-1.262). The cut-off value of the body mass index was 24.6 kg/m2 (male; 24.7, female; 24.6 kg/m2), with a sensitivity of 62.6% and specificity of 66.9%. Multiple logistic regression analysis for insulin resistance also gave the same results. Furthermore, the cut-off value of the body mass index for the metabolic syndrome as defined by NCEP-ATP III was also 24.1 kg/m2 (male; 24.0, female; 24.2 kg/m2).
CONCLUSIONS
Our study results suggest that the body mass index was the best surrogate marker for insulin resistance of a non-diabetic population and its cut-off value was approximately 24 kg/m2.