Prevalence of the metabolic syndrome using ATP-derived definitions and its relation to insulin-resistance in a cohort of Italian outpatient children

OBJECTIVE

To analyze the prevalence of the metabolic syndrome (MetS) defined by three sets of Adult Treatment Panel III (ATPIII)-derived criteria, and the ability of each definition to identify insulin-resistance (IR) in a wide cohort of outpatient children.

SUBJECTS AND METHODS

Seven hundred and twenty-four children consecutively observed in the Outpatient Pediatric Clinic of Pozzuoli Hospital during the period 2004-2009 were included in the study. Diagnosis of the MetS was made using three definitions: Cook, Jolliffe (which adopt age- and gender-specific cut-points) and de Ferranti. Insulin sensitivity was evaluated by homeostasis model assessment of insulin resistance (HOMA-IR). IR was defined by the 90th percentile of HOMA-IR in healthy non-obese Italian children grouped by gender and Tanner stage. The ability of each definition to identify IR was evaluated in terms of sensitivity and specificity.

RESULTS

The prevalence of the MetS in the overall cohort was 11, 12 and 24% using Cook, Jolliffe and de Ferranti criteria, respectively. Sensitivity and specificity in relation to IR were 19 and 94% with Cook criteria, 21 and 92% with Jolliffe criteria, and 39 and 84% with de Ferranti criteria.

CONCLUSIONS

The prevalence of the MetS in children increases with increasing body weight. Among the three definitions analyzed, de Ferranti identifies a larger number of children with the MetS. The prediction of IR is weak with all definitions; on the contrary, the absence of MetS identifies fairly well children with low degree of IR.

Central adiposity and left ventricular mass in obese children

AIM

The impact of central adiposity on left ventricular (LV) mass in childhood obesity has been little explored. This study evaluates whether central obesity influences LV mass and function in obese children.

METHODS AND RESULTS

Biochemical, anthropometric and echocardiographic measurements were taken in obese (n=111, mean age 10.6+/-2.5 years) and non-obese children (n=30, mean age 10.8+/-3.0 years). Left ventricular function was analyzed by conventional and tissue Doppler echocardiography. LV mass was calculated according to the Penn convention and indexed for height(2.7) (LVM(i)). The obese group showed increased levels of LVM(i) as compared to the non-obese group (35.7+/-8.5 vs 23.5+/-2.8 g/h(2.7), p<0.0001). Among obese children, we observed a significant increase of LVM(i) across tertile of waist-height ratio (WHtR). The subjects identified by the highest tertile of WHtR, as compared to subjects identified by the lowest tertile, showed higher levels of BMI (29.5+/-5.4 vs 31.0+/-5.0 kg/m(2), p<0.0001) and LVM(i) (32.1+/-6.5 vs 37.1+/-8.5 g/h(2.7), p<0.01). Among obese children a positive correlation (standardized for age and gender) was found between LVM(i) and BMI (r=0.282, p<0.01) and WHtR (r=0.334, p<0.0001). To analyze the independent predictors of LVM(i), a stepwise linear regression analysis was performed using age, gender, BMI, blood pressure, heart rate, HOMA-IR and WHtR as independent variables. LVM(i) was independently associated only with WHtR (beta=0.309, t=3.238, p=0.002).

CONCLUSION

Obese children show an increased LVM(i) and a preserved LV function. Central adiposity is the major determinant of left ventricular mass.