Weight and body mass index (BMI): current data for Austrian boys and girls aged 4 to under 19 years

Background: BMI reference charts are widely used to diagnose overweight, obesity and underweight in children and adolescents. Aim: To provide up-to-date national reference values for Austria. Methods: A cross-sectional sample of over 14 500 children and adolescents (4-19 years) stratified by provinces according to age-and sex-specific population proportions was drawn via schooling institutions (kindergartens, schools and vocational colleges). The generalized additive models for location, scale and shape were used for a flexible estimation of percentile curves. Results: Austrian boys and girls have higher average weight compared with previous prevalence data. BMI centiles matching BMI values at age 18 years, which are used for defining thinness, overweight and obesity in adults, were calculated. In Austria, using reference values as thresholds, similar to 18% of boys and 12% of girls are overweight (with thresholds passing through BMI 25.00-29.99 kg/m(2) in adults) and 5% of boys and 3% of girls are obese (with thresholds passing through BMI >= 30.00 kg/m(2) in adults). Conclusion: Overweight and obesity are common in Austria and their prevalence is increasing (using the same IOTF reference for international comparison). Up-to-date national BMI reference values are provided to classify children and adolescents according to the proposed overweight and obesity thresholds.