Major differences in prevalence of overweight according to nationality in preschool children living in Germany: determinants and public health implications

Aims: To investigate the prevalence of overweight according to nationality in preschool children living in Germany, and to establish the determinants responsible for differences in body mass index. Methods: The study was performed within the context of the 2001/2002 obligatory health examination before school entry in the city of Aachen, Germany. Of 2020 eligible children 1979 children were recruited (participation rate: 98%). Children's height and weight were measured using a standardised protocol. The parents completed a standardised questionnaire on sociodemographic factors and possible determinants of nutritional status. Being overweight was defined according to age and sex specific reference values for German children as well as according to international reference values. Results: The study population included 452 (22.9%) children with other than German nationality. Among these children the prevalence of overweight was twice as high than among German children (14.8% v 7.2%). Prevalence of most known risk factors for overweight, such as low physical activity, high consumption of soft drinks, and frequent visits to fast-food restaurants was higher in the children with other nationalities than in the German children. Multivariate analyses revealed that most of the difference in prevalence of obesity by nationality is explained by known risk factors of overweight, especially education of mother and watching TV. Conclusions: The apparent ethnic differences could be explained by two non-ethnic but socioeconomic factors. In preventing overweight in children, there is the need to identify and deal with high risk environments rather than high risk ethnic groups.