Background: School entry marks a tremendous change in the children's life style, which might well be relevant for the emergence of overweight. Previous studies suggested a dramatic increase in the prevalence of overweight during this age.
Objective: To compare the age-specific balance between the incidence and remission of overweight between pre-school and primary school age children.
Design: We combined the data of three studies that had been conducted within the setting of the compulsory school entry health examination in different parts of Germany: one covering retrospective cohort data from age 2 to school entry (n=5045), one prospective data from school entry to fourth grade (n=1235) and one comprising both (n=1194). We assessed the rates of incidence and remission of overweight and obesity from age 2 to school entry and from school entry to fourth grade.
Results: In pre-school age, the pooled incidence for overweight was 8.2% (95% confidence interval: 7.5, 8.9) compared with a remission rate of 62.6% (58.4, 66.7), yielding a prevalence at school entry of 10.7% (9.9, 11.5). In primary school age, the pooled incidence for overweight increased to 14.6% (13.1, 16.1), whereas the remission rate was reduced to 17.7% (13.8, 22.3), yielding a prevalence of 23.7% (22.0, 25.4) in fourth grade. A similar pattern was observed for obesity.
Conclusions: While high remission rates balance incident overweight in pre-school years, the dramatic increase in the prevalence of overweight and obesity in primary school years reflects a higher incidence and even more a lower remission rate. Obesity prevention programs in primary school age are mandatory and need to address primary and secondary prevention elements.