BMI values and other anthropometric and functional measurements as predictors of obesity in a selected group of adolescents.

Background: Obesity is well known to be a problem all over the world: WHO data report that one billion subjects are overweight and 300 million are obese. Epidemiological data (IOTF) show that prevalence rates are increasing not only in industrialized countries, but also in developing countries, especially as far as the adolescent population is concerned.

Aim Of The Study: To select adolescents at risk of obesity by BMI calculation and by other anthropometric and functional measurements in the Aosta Valley Mountain Region (Northern Italy).

Methods: 532 adolescents were recruited and participated in the study (254 males and 278 females, aged 15.4 +/- 0.7). According to standard methods, the following parameters were measured: weight and height for BMI calculation, four skin folds (mid-triceps,mid-biceps, subscapular and supra-iliac) to compute body fat mass,waist and hip circumferences, systolic (SBP) and diastolic (DBP) blood pressure. Parental weight and height, educational and socio-economic status were requested from the parents using a questionnaire.

Results: Percentages of overweight and obese boys were 20.9% and 4.7% respectively, and percentages of overweight and obese girls were 14.7% and 1.1% respectively (using Cole's cut off point reference standard). Mean body fat mass percentages (males = 19.3 +/- 5.6%, females 23.3 +/- 4.4%) showed males at risk of obesity, as indicated by a higher prevalence rate of overweight and obesity in this gender. Positive correlations (p <0.01) were found between BMI and the following parameters: mid-triceps skinfolds, body fat mass percentage,waist and hip circumferences, but no correlation emerged with WHR; body fat mass positively correlates (p <0.01) with waist and hip circumferences; students' BMI positively correlates with blood pressure (p <0.01),with parental BMI and shows a positive trend towards parental low education and socioeconomic levels.

Conclusions: Overweight and obesity prevalence rates are higher in males than in females according to literature data; family influences weight condition. The correlations that emerged show that BMI is a good adiposity index also in adolescents, it acts as an indicator of cardiovascular risk condition and is influenced by parental BMI.