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.