[Effectiveness of an educational video on infant crying for prevention of shaken baby syndrome among Japanese caregivers of infants].

Objectives　Spreading awareness of shaken baby syndrome is considered to be essential in the prevention of infant deaths resulting from abuse. This study aimed to determine whether an educational video on infant crying, developed by the Ministry of Health, Labour and Welfare, was effective at increasing knowledge of infant crying and shaking among Japanese caregivers of infants aged under 1 year.Methods　We targeted caregivers who had infants aged under 1 year for intervention through health checkups and home visits in 29 municipalities across Japan from April 2013 to March 2014. The educational video on infant crying and danger of shaking and smothering was used as intervention. A questionnaire was administered to caregivers to assess their knowledge on infant crying and shaking prior to and after the intervention (N=1,444, response rate 93.8%). A sample of 1,232 caregivers was used for analysis, after excluding those who did not report the outcome of interest (i.e., knowledge on shaking or smothering) and demographics. In the analysis, pre- and post-test mean scores on crying knowledge scales and shaking knowledge scales (out of 100) were compared separately. Subgroup analysis and regression analysis were also conducted to examine whether the effect of the intervention varied by infant age, birth order, parent's sex, age, education, marital status, household income, grandparents' co-residence, postpartum depression, domestic violence during pregnancy, feelings about pregnancy, and resident area (urban/rural).Results　Scores on infant crying significantly increased by 12.4 points (95% confidence interval: 11.7-13.2), and those on shaking knowledge increased by 4.7 points (95% confidence interval: 3.9-5.6) after the caregivers had watched the educational video. Subgroup analysis confirmed that the effect of the intervention did not differ among the subgroups except shaking knowledge scores among those who were not married and those who experienced physical violence from their partner. A regression analysis on change in scores revealed that parents with higher education gained more knowledge on infant crying, and fathers and those not living with grandparents gained more knowledge on shaking than mothers.Conclusion　The educational video on infant crying was effective in increasing knowledge of infant crying and shaking, regardless of demographics of infants and parents and postnatal situation.