Secular trends in body mass index in German children and adolescents: a cross-sectional data analysis via CrescNet between 1999 and 2006.

To assess secular trends in alterations in body mass index (BMI) in German children and adolescents between 1999 and 2006, we performed an analysis using data from a computerized database (CrescNet) and focusing on the data ranges above the 97th percentile (P97) and below the median (P50). This cross-sectional assessment of BMI data used a total of 143 495 single values (73 290 males and 70 205 females aged 0.5-17.5 years) from screening and/or consulting visits at 1 of the 294 participating German pediatricians. Body mass index data were calculated from standardized measurements of body weight and height entered into the CrescNet database. Individual percentiles were estimated according to German reference data sets. Across all age groups, the respective mean value of children with BMI above P97 increased from 5.32% to 7.02% in boys and from 5.70% to 7.18% in girls between 1999 and 2006, whereas those below P50 decreased from 48.52% to 43.71% in boys and from 47.48% to 42.57% in girls. The proportions of obese children (above the 97th percentile) were significantly higher than estimated by German reference values throughout the study period. The significant increase in childhood obesity between 1999 and 2006 was more pronounced in boys compared to girls. In conclusion, the cross-sectional study performed at a large cohort of German children and adolescents reveals an alarming increase in the number of obese children and adolescents and an accompanied shift toward higher BMI values. As the number of children below the 50th centile decreases accordingly, the shift in the distribution panel of the German reference percentile curves affecting the whole population can be observed.