[Association between cosleeping and emotional-behavioral problems and its differences with or without sleep anxiety...

Objective: To investigate the association between cosleeping and emotional-behavioral problems in preschool children, and analyze their differences across sleep anxiety status. Methods: A data analysis was conducted from June 2024 to October 2025. The prospective cohort data were derived from the Shanghai Children's Health, Education and Lifestyle Evaluation-Preschool cohort (SCHEDULE-P). Using a stratified cluster random sampling method, 20 899 newly enrolled preschool children from 191 kindergartens in Shanghai were recruited in November 2016 completed the first survey. Follow-up surveys were carried out in April 2018 and April 2019, during which parents completed structured questionnaires. Children's emotional-behavioral problems including emotional problems, conduct problems, hyperactivity problems, peer relationship problems, and prosocial behavior problems were assessed using the strengths and difficulties questionnaire (SDQ). Children's sleep quality was evaluated by the children's sleep habits questionnaire (CSHQ). The sleep anxiety status was evaluated by the sleep anxiety subscale and cosleeping status was reported via the question "Does the child sleep alone in their own bed?" of CSHQ. Mixed-effects Logistic regression models were used to examine the relationship between cosleeping and emotional-behavioral problems. A moderation model was constructed by including the interaction term between cosleeping and sleep anxiety, and further stratified analysis were conducted by dividing children into 2 groups based on the presence or absence of sleep anxiety, to clarify the association between cosleeping and emotional-behavioral problems within each group. Results: After excluding invalid data, a total of 15 679 children were included in the final analysis, including 8 082 boys (51.5%) and 7 597 girls (48.5%). The age was (3.73±0.29) years and 75.7% (11 872/15 679) of the children practiced cosleeping at the first survey. The mixed-effects Logistic regression model showed that preschool children who practiced cosleeping had a higher risk of emotional-behavioral problems compared with those who slept independently (OR=1.12, 95%CI 1.03-1.21, P=0.006), particularly in the domains of emotional problems, hyperactivity problems, and prosocial behavior problems (all P<0.01). The moderation model indicated statistically interaction effects between cosleeping and sleep anxiety on the total score and all subscales of SDQ (all P<0.01). Simple effect analyses revealed that among children with sleep anxiety, cosleeping was associated with lower risks of emotional-behavioral problems (OR=0.87, 95%CI 0.77-0.99, P=0.033), especially in peer relationship and conduct problems (both P<0.05).In contrast, among children without sleep anxiety, cosleeping was associated with higher risks of peer interaction and prosocial behavior problems (both P<0.05). Conclusions: The association between cosleeping and emotional-behavioral problems differs depending on the presence of sleep anxiety in preschool children. For children with sleep anxiety, cosleeping is linked to fewer emotional-behavioral problems; whereas for children without sleep anxiety, cosleeping tends to be associated with more emotional-behavioral problems.