Peer-reviewed article
Preschool care early in life and mental health in adolescence in Sweden: a cohort study.
László KD, Chen H, Andersson F, Galanti MR ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This Swedish cohort study followed adolescents born in 2000-2001 to examine whether the age at which they started preschool and hours spent there were linked to mental health problems in their teenage years. Children who started preschool between 12-15 months had higher rates of overall behavioural difficulties and externalising problems compared to those who started at 20 months or later. However, the study found weak overall evidence for a meaningful connection, with no link to internalising problems, and the public health impact appears limited.
Key points
- Children enrolled in preschool at 12-15 months had 1.39 times higher odds of high overall problems and 1.52 times higher odds of externalising problems compared to those enrolled at 20 months or later
- Population attributable fractions were 8% for overall problems and 9% for externalising problems, suggesting limited public health significance
- No associations were found between age at preschool start and internalising problems
- No associations were found between average weekly hours at preschool and any mental health outcomes
- The authors note weak and inconsistent evidence overall, with results constrained by observational study methodology and multiple comparisons
Limitations
The study is observational rather than experimental, so causation cannot be established and unmeasured confounding may explain the associations. The authors acknowledge methodological constraints, multiple comparisons, and sample selection as limitations that affect interpretation.
Abstract
Objective Despite the high rates of early enrolment in preschool and of poor mental health in adolescence in Sweden, knowledge regarding their association in Sweden is lacking. We investigated whether age at starting preschool and weekly hours spent at preschool in different ages are associated with mental ill-health in Swedish adolescents. Design A cohort study based on data from KUPOL (Swedish acronym for 'Knowledge about Adolescents Mental Health and Learning'). Setting and participants We used data from KUPOL, a longitudinal study conducted during 2013-2018, involving Swedish adolescents born 2000-2001. We included in the current analyses adolescents with available information on the exposures and the outcomes of interest (n=2261). Outcome measures Study participants and their parents completed questionnaires concerning the child's age (in months) at start of preschool, the average weekly hours in preschool in different ages, the adolescent's mental health, lifestyle, school-related, psychosocial and parental sociodemographic factors. We analysed the association between preschool-related factors and mental health using logistic regression. Results Children enrolled in preschool at the age of 12-15 months had increased odds of high overall and externalising problems score on the Strengths and Difficulties Questionnaire relative to those enrolled at 20 months or later. The corresponding ORs (95% CIs) were 1.39 (95% CI 1.02 to 1.90) and 1.52 (95% CI 1.08 to 2.16), while the corresponding population attributable fractions were 8% and 9%, respectively. There were no associations between age at start of preschool and internalising problems, nor between the average weekly hours at preschool and mental health. Conclusion We found weak and inconsistent evidence for a link between early preschool attendance and mental health in adolescence; population attributable fractions suggest limited public health implications for the studied associations. The results should be interpreted in light of the methodological constraints of observational studies, the multitude of our comparisons and the sample selection.