Insulin resistance is a risk factor for high blood pressure regardless of body size and fat distribution in obese children

Background and aim: The prevalence of children with hypertension is increasing, especially in obese children. This study was to assess the relationship between blood pressure, indexes of adiposity, body fat distribution and insulin resistance. Methods and results: Sample: 1044 children (M/F: 484/560; aged 6-11 years). Anthropometry and blood pressure were measured and fasting blood samples were tested for triacylglycerol, total cholesterol, HDL cholesterol, glucose, insulin and ALT. The prevalence of high blood pressure in overweight males and females was 14.3 and 6.4%, respectively (chi(2) = 16.73, p < 0.001) and in obese it was 40.4 and 32.8%, respectively (chi(2) = 5.56, p < 0.001). High blood pressure increased progressively with BMI z-score categories (chi(2) = 67.99, p < 0.001) as well as with waist/height ratio (W/Hr) categories (chi(2) = 23.51, p < 0.001). Hypertensive subject had significantly higher insulin (15.6 +/- 9.8 vs 11.9 +/- 7.2, p < 0.001 and 20.63 +/- 14.7 vs 15.26 +/- 9.8, p < 0.001 in males and females respectively) and HOMAIR (3.23 +/- 2.1 vs 2.42 +/- 1.49, p < 0.001 and 4.12 +/- 2.87 vs 3.07 +/- 1.98, p < 0.001 in males and in females, respectively) than non-hypertensive ones. Among metabolic and cardiovascular risk factors, HOMAIR was the only variable able to predict high blood pressure in obese boys and girls, in addition to BMI or body fat distribution (waist, W/Hr). The highest HOMAIR category was the most important predicting factor of high blood pressure in overweight and obese children in addition to body size or body fat distribution. Conclusions: Blood pressure is associated with the degree of overweight and the indices of body fat distribution. Insulin resistance is an independent additional risk factor for hypertension. (C) 2009 Elsevier B.V. All rights reserved.