Clustering of Risk Variables in Insulin Resistance Syndrome in Jungup District, Korea

Kim, Sang Wook; Huh, Myung Hoe; Kim, Young Il; Kim, Jin Yub; Kim, Eun Sook; Lee, Moo Song; Park, Joong Yeol; Hong, Sung Kwan; Lee, Ki Up

Abstract

BACKGROUND: Insulin resistance syndrome (IRS), a clustering of hypertension, impaired glucose tolerance, low HDL cholesterol and high triglyceride, is prevalent in Korea. We studied the correlational structure of IRS using factor analysis to evaluate whether a single process underlies in the clustering of these risk factors.
METHODS
Factor analysis was performed using data from 1,018 non-diabetic subjects (388 men and 630 women) who participated in the Jungup epidemiological study. RESULTS: Factor analysis reduced 9 correlated risk factors to 4 independent factors, each reflecting a different aspect of IRS: hypertension factor (increased systolic and diastolic blood pressure), glucose intolerance factor (increased fasting and postload glucose), obesity factor (increased body mass index, waist circumference, and increased insulin), and dyslipidemia factor (increased trigly- cerides and decreased HDL cholesterol). Increased insulin was also loaded into dyslipidemia factor in men and glucose intolerance factor in women. These factors explained about 70% of the total variance in the data. Three factors such as the glucose intolerance factor, the dyslipidemia factor and the obesity factor, were linked through mutual association with hyperinsulinemia, while hypertension factor was not associated with hyperin- sulinemia. Age-adjusted mean BP by BMI tertile and fasting insulin level tertile for men and women increased progressively with increase in BMI in men and women. There was no significant elevation of mean BP according to increase in fasting insulin level. In contrast to premenopausal women in whom hyperinsulinemia show mutual association with the glucose intolerance factor, the dyslipidemia factor, and the obesity factor, hyperinsulinemia was only loaded into obesity factor in postmenopausal women.
CONCLUSION
These results suggested that more than one process underlies the clustering of IRS. In sulin resistance alone did not seem to be the single underlying mechanism of IRS. Especially, hypertension was not correlated with hyperin- sulinemia.