Background Oxidative stress is elevated in obese youth, but less is known regarding racial disparities in the relationship of oxidative stress with metabolic risk factors. Objectives To determine the relationship between oxidative stress and metabolic risk factors, adiposity, leptin, adiponectin, and cardiovascular fitness (VO2PEAK) in healthy African American and White American youth. Methods A marker of oxidative stress (F2-isoprostane), validated markers of metabolic risk factors, fitness and body composition were measured in African American (n=82) and White American (n=76) youth (8–17 years old) recruited over a range of body mass index (BMI) percentiles (4th to 99th). Results F2-isoprostane concentration was positively correlated with percentage body fat (r=0.198) and percentage truncal fat (r=0.173), but was not different between African American and White American males and females (p =0.208). African American youth had significantly higher mean systolic and diastolic blood pressure (p =0.023 and p =0.011, respectively). After adjusting for gender, age, BMI, and Tanner stage, African American youth varied from White Americans in the association of F2-isoprostane with diastolic blood pressure (p =0.047), but not with systolic blood pressure, triglycerides, VO2PEAK, or HOMA-IR (all p>0.05). Conclusions Oxidative stress, as measured by urinary F2-isoprostane concentrations, was positively associated with percent body fat and percent truncal fat in youth. Oxidative stress levels were similar among African American and White American youth. Among markers of the metabolic syndrome, a significant difference between African American and White American youth was demonstrated only in the association of oxidative stress with diastolic blood pressure.

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Objective To compare the accuracy of body composition measurements to small, defined changes in fat mass between dual X-ray absorptiometry (DXA) and air-displacement plethysmography (ADP). Methods Fifty-six healthy adults, 29 women and 27 men (age, 38 ± 12.4 years; BMI, 27.6 ± 5.8 kg/m2) were included in the study. Exclusion criteria were pregnancy, indwelling metal hardware or pacemakers, or weight exceeding DXA table limit (>350 lbs). All individual testing was completed within a 2-hour period. Fat packets were prepared using lard wrapped in plastic and applied exogenously in defined locations. Each participant completed body composition measurements with ADP and DXA (both testing modalities completed with and without 1 kg of exogenously applied fat mass). Results Both DXA and ADP were highly accurate in detecting an overall increase in body mass associated with exogenously applied 1kg of fat mass (0.99 kg vs. 0.97 kg, respectively). DXA more accurately detected exogenous fat increase as fat mass compared to ADP (0.93 kg; 90% CI for the mean of the difference: 0.83 to 1.03 kg vs. 0.45 kg; 90% CI: 0.19 to 0.71 kg, respectively). The accuracy of body mass detection was similar for males and females (0.97 vs. 1.02 for DXA and 0.92 vs. 1.02 for ADP, respectively), though accuracy in detecting added mass as fat was less accurate in males than females (0.84 vs. 1.00 for DXA and 0.39 vs. 0.51 for ADP, respectively) Discussion Both DXA and ADP are accurate in detecting an overall increase in body mass associated with exogenously applied 1kg of fat mass. However, DXA is more accurate than ADP in correctly identifying the increase in body mass as fat mass, as opposed to fat free mass.

Background:Pulmonary aspiration during sedation is a major concern for sedation providers, making identifying high-risk patients a priority. Gastric fluid volume (GFV), an accepted risk factor for aspiration, has not been well characterized in fasting children. We hypothesized that GFV would increase with gastrointestinal (GI) pathology and decrease with regular acid-suppressor use.Aims:The primary objective was to determine baseline GFV in fasting children. The secondary objectives were to evaluate the effect of GI pathology and regular use of acid-suppressing medications on GFV.Settings and Study Design:This was prospective, observational study.Materials and Methods:We endoscopically aspirated and measured GFV of 212 children fasting for >6 h who were sedated for esophagogastroduodenoscopy (EGD). Inclusion criteria were children up to 21 years of age, with the American Society of Anesthesiologists physical Status I and II presenting for elective EGD. After determining baseline GFV, the effect of GI pathology and effect of regular acid-suppressing medication use on GFV was analyzed.Statistical Analysis:Analysis of variance was used to compare the GFV among ages and pathology and medication groups. Student's t-test was used to compare GFV between genders and also to compare GFV in confounder analyses.Results:For the studied 212 children, average GFV was 0.469 ± 0.448 mL/kg (0–2.663 mL/kg). We found no association between GI pathology and GFV (P = 0.147), or acid-suppressor use and GFV (P = 0.360).Conclusions:Average GFV in this study falls within the range of prior EGD-measured GFV in fasting children. Contrary to our hypothesis, we found no association between pathologies or regular acid-suppressor use on GFV. On the basis of GFV, children with GI disorders or those using acid-suppressors do not appear to pose an increased risk of aspiration. Future studies should discern differences in effects on GFV of immediate preprocedural versus the regular use of acid-suppressing medications.