Metabolic syndrome in obese adolescents is associated with risk for nephrolithiasis.

OBJECTIVES: To examine the relationship between urinary pH and metabolic syndrome risk factors along with insulin resistance in obese adolescents, and to evaluate the relationship between other urinary stone-forming and -inhibiting markers and metabolic syndrome. STUDY DESIGN: A total of 46 obese adolescents were enrolled. Twenty-four hour and randomly obtained urine samples were analyzed for urinary pH, promoters of stone formation (ie, uric acid, oxalate, and relative saturation ratio of calcium oxalate [RSR-CaOx]), and inhibitors of stone formation (ie, citrate and osteopontin). Other data collected included height, weight, blood pressure, and fasting lipid, insulin, and glucose levels. RESULTS: The subjects had a mean age of 14.6±2.0 years and a mean body mass index of 36±6.3 kg/m(2). Random urine pH and the number of risk factors for metabolic syndrome were negatively correlated (r=-0.34; P=.02). RSR-CaOx was correlated with both homeostasis model assessment of insulin resistance score (r=0.38; P<.01) and number of risk factors for metabolic syndrome (r=0.47; P=.001) CONCLUSION: Decreased urinary pH and increased RSR-CaOx are associated with risk factors for metabolic syndrome in obese adolescents.

The abnormal measures of iron homeostasis in pediatric obesity are associated with the inflammation of obesity.

Objectives. To determine if the low iron state described in obese children is associated with the chronic inflammatory state seen in obesity. Study Design. Obese children age from 2 to 19 years seen at a weight management clinic were studied prospectively. Data were collected on age, gender, BMI, BMI z-score, serum iron, ferritin, transferrin saturation, free erythrocyte protoporphyrin, high sensitivity creactive protein (hs-crp), and hemoglobin concentration. Results. 107 subjects were studied. Hs-crp levels correlated positively with BMI (P < .001) and BMI z-score (P = .005) and negatively with serum iron (P = .002). 11.2% of subjects had low serum iron. Median serum iron was significantly lower for subjects with American Heart Association high risk hs-crp values (>3 mg/L) compared to those with low risk hs-crp (<1 mg/L), (65 mcg/dL versus 96 mcg/dL, P = .016). After adjusting for age, gender, and BMI z-score, serum iron was still negatively associated with hs-crp (P = .048). Conclusions. We conclude that the chronic inflammation of obesity results in the low iron state previously reported in obese children, similar to what is seen in other inflammatory diseases.