Association between Oxidative Stress and Masked Hypertension in a Multi-Ethnic Population of Obese Children and Adolescents

Objective To evaluate whether oxidative stress is correlated with adiposity, obesity-related metabolic abnormalities, and ambulatory blood pressure (ABP) in a multi-ethnic pediatric population. Study design We conducted a prospective study enrolling 42 obese children (age, 12.8 +/- 2.4 years) and 34 non-obese children (age, 11.8 +/- 3.4 years). We measured urine 8-isoprostane and hydrogen peroxide (markers of oxidative stress) in both obese and non-obese groups. In the obese group, we measured the 24-hour ABP and obtained an oral glucose tolerance test, lipid panel, interleukin-6, and tumor necrosis factor-a. Results 8-isoprostane and hydrogen peroxide were correlated with body mass index standard deviation score and waist circumference. The mean 8-isoprostane and hydrogen peroxide levels of the obese group were higher than those of the non-obese group. In the subset of obese subjects who underwent ABP monitoring, 8-isoprostane was correlated with mean 24-hour systolic blood pressure: within the obese group, 8-isoprostane was higher in obese children with elevated mean 24-hour systolic blood pressure. Conclusions Our findings provide evidence of a significant correlation between oxidative stress, adiposity, and blood pressure in children. Longitudinal studies in a larger population sample are needed to validate the association between elevated urine 8-isoprostane level and cardiovascular risk factors in an obese pediatric population. (J Pediatr 2011; 158:628-33).