Associations of visceral adiposity and exercise participation with C-reactive protein, insulin resistance, and endothelial dysfunction in Korean healthy adults

Abstract

The aim of the current study was to examine the associations of visceral adiposity and exercise participation with C-reactive protein (CRP), insulin resistance, and endothelial dysfunction in Korean adults selected from the general population. We studied 160 Korean adults (aged 41.3 +/- 13.0 years; n = 38 men and n = 122 women) who volunteered in a health promotion program. Subjects were divided into 2 groups based upon spontaneous exercise participation for using a cross-sectional approach. We measured anthropometric factors (body mass index [BMI], percentage body fat, waist-hip ratio [WHR], and abdominal fat area by computed tomographic scanning), blood pressure (BP), blood levels of glucose, lipids, fibrinogen, CRP, leptin, hemoglobin A(1c), homeostasis model assessment (HOMA), and carotid intima media thickness (IMT; via ultrasonography). Associations among the variables were assessed by Pearson partial correlation and linear regression, controlling for age and sex. Independent t tests were used to assess differences between exercise participants and nonparticipants. Significance was accepted at P < .05. As expected, the measures of adiposity (BMI, percentage body fat, WHR, abdominal fat area) were highly correlated with each other (r = .49-.86, P < .01). Blood levels of high-sensitivity CRP (hsCRP), leptin, and HOMA were modestly correlated with all measures of adiposity. Visceral fat area was the most important predictor of hsCRP, explaining 19.6% of the variance using stepwise linear regression analysis (P < .01). As visceral fat area tertiles increased from low to high, a significant stepwise increment in blood levels of CRP (P < .001), HOMA (P = .005), and left carotid IMT (P = .035) was observed. However, hsCRP and HOMA were not significantly different when compared across whole-body fat tertiles. Systolic BP, diastolic BP, and left carotid IMT were modestly correlated with WHR and visceral fat area (P < .05); but systolic BP and diastolic BP were also correlated with BMI and percentage body fat (P < .05). Therefore, the relative importance of central adiposity as opposed to total body fatness in endothelial dysfunction is unclear. Compared with the nonexercise group, exercise participants had significantly lower (P < .05) WHR, visceral fat area, ratio of visceral fat area to subcutaneous area, hsCRP, hemoglobin A(1c), and HOMA, with no significant differences in BMI, percentage body fat, and physical fitness. Central obesity with high visceral fat is strongly associated with blood level of hsCRP, insulin resistance, and endothelial dysfunction-related factors in healthy Korean adults. In addition, exercise participation, even in the absence of difference in physical fitness, may be protective against development of central obesity and insulin resistance in this understudied Korean population.