Developing a risk assessment tool for identifying individuals at high risk for developing insulin resistance in European adolescents: the HELENA-IR score.

OBJECTIVES: To develop and validate an easy-to-use screening tool for identifying adolescents at high-risk for insulin resistance (IR). METHODS: Α total of 1,053 adolescents (554 females), aged 12.5 to 17.5 years with complete data on glucose and insulin levels were included. Body mass index (BMI), fat mass index (FMI) and the homeostasis model assessment for insulin resistance (HOMA-IR) were calculated. VO2max was predicted using 20 m multi-stage fitness test. The population was randomly separated into two cohorts for the development (n=702) and validation (n=351) of the index, respectively. Factors associated with high HOMA-IR were identified by Spearman correlation in the development cohort; multiple logistic regression was performed for all identified independent factors to develop a score index. Finally, receiver operating characteristic (ROC) analysis was performed in the validation cohort and was used to define the cut-off values that could identify adolescents above the 75th and the 95th percentile for HOMA-IR. RESULTS: BMI and VO2max significantly identified high HOMA-IR in males; and FMI, TV watching and VO2max in females. The HELENA-IR index scores range from 0 to 29 for males and 0 to 43 for females. The Area Under the Curve, sensitivity and specificity for identifying males above the 75th and 95th of HOMA-IR percentiles were 0.635 (95%CI: 0.542-0.725), 0.513 and 0.735, and 0.714 (95%CI: 0.499-0.728), 0.625 and 0.905, respectively. For females, the corresponding values were 0.632 (95%CI: 0.538-0.725), 0.568 and 0.652, and 0.708 (95%CI: 0.559-0.725), 0.667 and 0.617, respectively. Simple algorithms were created using the index cut-off scores. CONCLUSIONS: Paediatricians or physical education teachers can use easy-to-obtain and non-invasive measures to apply the HELENA-IR score and identify adolescents at high risk for IR, who should be referred for further tests.

Cardiorespiratory fitness is associated with body composition and insulin resistance in European adolescents: HELENA study.

BACKGROUND: The present study aimed to examine the independent association between cardiorespiratory fitness, sedentary time and insulin resistance in European adolescents. METHODS: A subset (N.=1097) of a large multicenter European study (HELENA-CSS study) was used in the present study. Serum concentrations of glucose (GF) and insulin (IF) were measured after overnight fast and homeostasis model assessment (HOMA-IR) was calculated. Sedentary time and time spent on moderate-to-vigorous physical activity (MVPA) was objectively measured by accelerometers. Moreover, sedentary activities were self-reported via questionnaires. RESULTS: Multilevel linear regression analysis revealed that adolescents watching TV≥2 h/day had higher HOMA-IR (P=0.007). Further adjustment for MVPA, showed that watching TV≥2 h/day remained significantly associated with IR (P=0.002). In this model, MVPA was inversely associated with HOMA-IR (P=0.001). Further controlling for waist circumference showed that adolescents watching TV≥2 h/day continued to have higher HOMA-IR levels (P=0.002). Stratified analysis by weight status, revealed that watching TV≥2 h/day was independently associated with HOMA-IR only in normal weight adolescents, while MVPA was inversely associated with HOMA-IR in both overweight/obese and normal weight adolescents. Only the volume of maximum oxygen consumption (VO2max) over body fat mass ratio was inversely associated with HOMA-IR after controlling for several confounders. CONCLUSIONS: The present study showed that watching TV≥2 h/day and MVPA were associated with HOMA-IR. However, after controlling for several confounders, only VO2max/body fat mass ratio remained negatively associated with HOMA-IR. Future interventions should aim both to promote physical activity and reduce sedentary time in adolescents to improve their cardiorespiratory fitness and postpone the onset of diabetes in adulthood.

Prevalence of obesity in preschool Greek children, in relation to parental characteristics and region of residence.

BACKGROUND: The aim of this retrospective cohort study was to record the prevalence of overweight and obesity in relation to parental education level, parental body mass index and region of residence, in preschool children in Greece. METHODS: A total of 2374 children (1218 males and 1156 females) aged 1-5 years, stratified by parental educational level (Census 1999), were examined from 105 nurseries in five counties, from April 2003 to July 2004, Weight (kg) and height (cm) were obtained and BMI (kg/m2) was calculated. Both the US Centers for Disease Control (CDC) and the International Obesity Task Force (IOTF) methods were used to classify each child as "normal", "at risk of overweight" and "overweight". Parental demographic characteristics, such as age and educational level and parental anthropometrical data, such as stature and body weight, were also recorded with the use of a specifically designed questionnaire. RESULTS: The overall estimates of at risk of overweight and overweight using the CDC method was 31.9%, 10.6 percentage points higher than the IOTF estimate of 21.3% and this difference was significant (p < 0.001). Children with one obese parent had 91% greater odds for being overweight compared to those with no obese parent, while the likelihood for being overweight was 2.38 times greater for children with two obese parents in the multivariate model. CONCLUSION: Both methods used to assess prevalence of obesity have demonstrated that a high percentage of the preschool children in our sample were overweight. Parental body mass index was also shown to be an obesity risk factor in very young children.