Japanese fathers' work-related factors associated with involvement in childcare.

Objectives: Existing studies of fathers' involvement in childcare have focused on its impact on children's psychosocial development and the facilitation of family functions, like marital relationships. In this study, we investigated the factors that determine paternal childcare in Japan, particularly focusing on work-related hours and environment, separately, according to mothers' employment status.

Methods: We used data from the Longitudinal Survey of Newborns in the 21st Century (2010 cohort) conducted in Japan. We restricted the sample to 27 783 participants with working fathers and analyzed how paternal work-related factors affect fathers' childcare involvement by mothers' employment status using an ordered logistic regression model.

Results: In the model adjusting for all covariates, the odds ratio (OR) of spending less time with children on weekdays was higher: for fathers who worked 50 and more hours per week compared with those who worked 40-49 hours per week (OR = 1.95, 95% CI: 1.72-2.20 for 50-59 hours), for fathers whose commuting hours were longer than those commuting less than 0.5 hours per day (OR = 2.93, 95% CI: 2.34-3.69 for 1.5 or more hours), for larger workplace employee sizes than for 5-99 employee sizes (OR = 1.56, 95% CI: 1.38-1.77 for 500 or more employees). The associations between these paternal work-related variables and paternal hours spent with the children on weekdays were almost the same if the mothers were working or not working.

Conclusions: Regardless of whether the mother is working, fathers' work environment factors, such as working hours, play a key role in their involvement in childcare.