Early childhood physical activity behaviour and the development of overweight

Prevention of overweight should start at a young age and physical activity is considered a key factor in the prevention of overweight. However, in young children, the association between physical activity and the development of overweight is not clear. This thesis showed that evidence for an association between early childhood physical activity behaviour and the development of overweight is limited. In a systematic review and meta-analyses we found no associations between most of the intensities of physical activity and various outcomes for adiposity in children aged 2- to- 7 years. In two subsequent cross-sectional studies, we showed a clear, but different, pattern of physical activity and sedentary time throughout the day in young Dutch en Chinese children. In addition, in the Dutch study, children affected by overweight were not less active than children without overweight, but in the Chinese study children with overweight were overall more sedentary and they spent less time in light physical activity in multiple segments of the day compared to their peers. Then, we performed a prospective study in which we showed that young Dutch children’s physical activity behaviour was neither related to the development of overweight, nor to abdominal overweight and hypertension five years later. In our last study, we showed that other lifestyle factors during early childhood like diet, sleep and screen time seem to be more important in the development of overweight. Furthermore, we proposed a regional approach to target interventions more specifically to the children in need based on their lifestyle behaviour and their living environment.