Outcomes, exposures, and covariates
The questionnaire collected data on SDQ domains used as a measure of children’s behavioral problems, demographic characteristics of children and their caregivers, Parenting Stress Index short form (PSI-SF), and ISAAC scores. SDQ is an instrument used to evaluate both positive and negative infant, child, and adolescent behavior.20 It includes 25 items scored on a 3-point Likert-type scale across 5 domains; emotional problems, conduct problems, hyperactivity, peer problems, and prosocial behavior. The total difficulties score as assessed in this study consisted of the 4 domains excluding prosocial score, as that domain alone had a positive value. 20The total difficulties score was used as an outcome in this study. The Japanese SDQ, translated from the original version developed in the United Kingdom, has been validated and is considered applicable to children in Japan.21
The PSI is a self-reported measure of stress associated with childcare.22 The PSI-SF, which is an abbreviated version of PSI, consists of 19 items scored on a 5-point Likert-type scale. The Japanese PSI-SF has been validated and applied in this study.23,24 Parenting stress was divided into parent- and child-associated domains, and assessed comprehensively based on the total score. Higher scores indicated higher stress levels.