Serum lipids, serum insulin, plasma fibrinogen and aerobic capacity in obese and non-obese Singaporean boys

OBJECTIVES: To compare blood lipids, lipoproteins, apoproteins, fibrinogen, insulin and aerobic capacity in obese and nonobese Chinese Singaporean boy s. To examine relationships between blood metabolites, body composition and aerobic capacity in these groups. DESIGN: Cross-sectional SUBJECTS: Forty Chinese Singaporean boys aged 13 -15y Classified as obese ( n = 20) or non-obese (n = 20) based on adiposity (fat mass/fat free mass): > 0.60 = obese, < 0.40 = non-obese. MEASUREMENTS: Body composition (dual energy X-ray absorptiometry), waist ci rcumference, peak oxygen consumption (VO2 peak), serum concentrations of to tal cholesterol, triacylglycerol, high density lipoprotein cholesterol (HDL -C), total cholesterol/HDL-C, apoproteins Al and B, lipoprotein(a), insulin and glucose. Plasma concentration of fibrinogen. RESULTS: Obese boys had significantly (P < 0.01) higher (mean +/- s.d.) con centrations of serum triacylglycerol (1.51 +/- 0.65 vs 1.04 +/- 0.34 mmol/l ), serum insulin (24.1 +/- 11.5 vs 12.3 +/- 4.45 mU/I) and plasma fibrinoge n (4.01 +/- 0.54 vs 3.35 +/- 0.76 g/l) than non-obese boys. Within the non- obese group plasma fibrinogen concentration was significantly related to pe rcentage body fat (r = 0.546, P < 0.05). VO2 peak relative to body mass (ml /kg/min or ml/kg(-0.67)/min) was significantly (P < 0.001) lower in obese c ompared to non-obese boys but absolute VO2 peak (l/min), adjusted for fat-f ree mass via analysis of covariance, was higher in obese than non-obese boy s (P < 0.01). Partial correlations revealed that none of the blood metaboli tes were significantly related to VO2 peak independent of body fatness. CONCLUSIONS: Obesity was related to elevated concentrations of serum triacy lglycerol, serum insulin and plasma fibrinogen in Chinese Singaporean boys. These elevated concentrations did not appear to be associated with a lower aerobic capacity (independent of body fatness) in the obese.