Lipid corrected plasma alpha-tocopherol values are inversely related to fasting insulinaemia in obese children

Plasma concentrations of alpha-tocopherol and retinol were measured in 17 obese children (10 boys and 7 girls, age: 13.9 +/- 0.3 y, mean +/- s.e.m.) and related to anthropometric indices and fasting plasma insulin concentrations. Body weight was 89.0 +/- 5.3 kg, relative body weight 165 +/- 6%, body fat content 38.9 +/- 1.2% and body mass index 32.3 +/- 1.3 kg/m2. Plasma alpha-tocopherol, retinol and insulin concentrations were 18.5 +/- 1.6 mul/l, 2.0 +/- 0.2 mu/l and 17.2 +/- 1.6 mU/l, respectively. Neither alpha-tocopherol nor retinol concentrations were related to age. Plasma retinol concentrations were positively correlated to weights (r = 0.60, P = 0.01) and heights (r = 0.65, P < 0.01), but not to body fat contents. In contrast, plasma alpha-tocopherol concentrations were not related to weights and heights, but a significant inverse relation was seen to body fat contents (r = -0.49, P = 0.04). Fasting plasma insulin concentrations did not correlate with plasma retinol values, but were inversely related to plasma alpha-tocopherol concentrations (r = -0.53, P = 0.02) and alpha-tocopherol: cholesterol+triglyceride ratios (r = -0.57, P = 0.01). These results indicate that the factors influencing the availability of retinal and alpha-tocopherol in obese children may be different.