How does the family background relate to obesity in children and adolescents? Cross-sectional and longitudinal analysis based on the German multicenter BZGA observational study [Abstract] - Ulrike Hoffmeister and Monika Bullinger and Cornelia Goldapp and Reinhard Mann and Ulrike Ravens-Sieberer and Thomas Reinehr and Andreas van Egmond-Fröhlich and Joachim Westenhöfer and R.W. Holl (Obesity Facts, 2009)