Relationship of body fat with insulin resistance and cardiometabolic risk factors among normal glucose-tolerant subjects

Background: The amount of body fat, rather than the amount of excess weight, determines the health risks of obesity, type 2 diabetes mellitus, and cardiovascular disease. Aims: To look at the association of body fat percentage with cardiometabolic risk factors in subjects with normal glucose tolerance (NGT). Settings and Design: Cross-section study from the Chennai Urban Rural Epidemiology Study. Materials and Methods: Body fat was measured by Beurer body fat analyzer. Metabolic syndrome (MS) was diagnosed based on modified ATPIII guidelines. Statistical Analysis: Student's t test or one-way ANOVA (with Tukey's HSD) was used to compare groups for continuous variables. Results: Body mass index, waist circumference, systolic and diastolic blood pressure, HOMA IR, serum cholesterol, and LDL cholesterol increased significantly with increasing tertiles of body fat (P < 0.001). There was a linear increase in the percentage of body fat with increase in number of components of MS (no metabolic abnormality: 25 +/- 11, one metabolic abnormality: 28 +/- 10, two metabolic abnormalities: 33 +/- 8, and three and more metabolic abnormalities: 35 +/- 7) (P < 0.001). Regression models showed significant association of body fat with MS after adjusting for age, gender, insulin resistance, and glycated hemoglobin (Odds ratio: 1.04, 95% confidence interval: 1.04 -1.08, P < 0.001). In linear regression analysis, body fat showed a significant association with insulin resistance after adjusting for age, gender, and glycated hemoglobin (beta=0.030, P < 0.001). Conclusions: A significant association exists between body fat, MS, and cardiometabolic risk factors even among subjects with NGT.