Michel S. Smit

Previous studies conducted mainly among adolescents have found associations between participation in sport organised leisure-time activities (OLTAs) and mental health problems (MHP). Fewer research studies have been performed to primary school-aged children and to organised non-sport OLTAs. Therefore, the objective is to examine whether there is an association between participation in sport and non-sport OLTAs and a high risk of MHP in 4- to 12-year-olds. Data were used on 5010 children from a cross-sectional population-based survey conducted between May and July 2018 in Rotterdam, the Netherlands. Associations between sport OLTAs, non-sport OLTAs and breadth of OLTAs and a high risk of MHP were explored using logistic regression models adjusting for sociodemographic characteristics, stressful life events and physical activity. Of all children, 58% participated in sport OLTAs and 22% in non-sport OLTAs. The proportion of children with high risk of MHP among participants in sport OLTAs is smaller than among non-participants (OR 0.66, 95% CI: 0.53, 0.81). The proportion of children with high risk of MHP among participants in non-sport OLTAs is smaller than among non-participants (OR 0.69, 95% CI: 0.53, 0.91). The proportion of children with a high risk of MHP among participants in 1 category of OLTAs (OR 0.61, 95% CI: 0.49, 0.76) and in 2–5 categories of OLTAs (OR 0.48, 95% CI: 0.32, 0.71) is smaller than among non-participants.  Conclusion: The proportion of children with high risk of MHP among participants in OLTAs is smaller than among non-participants. What is Known:• Around 10–-20% of children and adolescents experiences mental health problems.• Sport organised leisure-time activities have been found to be associated with a lower risk of mental health problems in adolescents. What is New:• The proportion of children with a high risk of mental health problems in participants in organised leisure-time activities is smaller than among non-participants.• The proportion of children with a high risk of mental health problems in participants with a higher breadth of organised leisure-time activities is smaller compared to non-participants.