[Prevalence of overweight and obesity in children and adolescents from 1977 to 2009 - examination of the school medical data of more than 94,000 school-age children in the city of Basel (Switzerland)].

OBJECTIVES: A cross-sectional study over a period of 30 years was used to investigate the development of overweight and obesity in school children. Of particular interest is the question of whether the overweight epidemic is continuing to increase, as often postulated, or whether a stagnation point or the start of a reversal of the trend has already been reached.
METHODS: School medical examinations take place at three school levels in the city of Basel. 94,004 student files from these examinations from the school years 1977/78 and 1978/79, as well as from 1989/90 to 2008/09, have been subjected to a secondary analysis. The overweight and obesity prevalences were calculated for eleven 2-year cohorts according to the standards of the International Obesity Taskforce IOTF. A more in-depth analysis followed, differentiated by school grade, gender and nationality.
RESULTS: The percentage of overweight and obese children and young people has increased strongly in the last 3 decades. Whereas every 11th child was overweight 30 years ago (9.3%), it now amounts to every 5th child (20.9%). The proportion of obese children has increased from 1.2% to 5.4%. The large increase in overweight and obesity prevalences mainly took place in the 1990s. Since the millennium change, the number of overweight and obese school children among those examined has only increased slightly, or has at least no longer increased. This general development was observed in all school grades and was independent of gender and nationality, although foreign children are always twice as likely to be affected by overweight and obesity. The stabilisation can be seen at its earliest and the change in trend is clearest in the kindergarten, which could indicate a "year's cohort effect".
CONCLUSIONS: The development over the last 10 years is welcome from a public health point of view. The continued high prevalence still represents a significant health problem, however, and the prevention efforts being made against the overweight epidemic must be further strengthened. © Georg Thieme Verlag KG Stuttgart · New York.