Birth order and socioeconomic disadvantage predict behavioural and emotional problems at age 3 years

Aim The aim of this study was to describe sociodemographic and family predictors for behavioural and emotional problems in pre-schoolers. Methods This was a cross-sectional study including 30,795 children in the Stockholm region whose parents had completed the Strength and Difficulties Questionnaire (SDQ) prior to a routine visit to a well-baby clinic at age 3 years. Multivariate logistic regression was used to analyse predictors for having a high total SDQ difficulties score. Results Young parental age and a low level of parental education predicted high total SDQ score in a stepwise pattern. Being a first-born child was associated with a high SDQ score with an adjusted odds ratio of 2.10 (95% C.I. 1.84-2.41), compared with having older siblings. A sole physical custody arrangement predicted a high total SDQ score after parental separation. The percentage of children with a high total SDQ score increased with the Care Need Index (CNI) of the well-baby clinic. Conclusions This study identified socioeconomic disadvantage and being the first-born child as the main predictors of poor mental health at age 3 years. Well-baby clinics with socioeconomically disadvantaged catchment areas should be provided with adequate resources and methods for equitable prevention.