Associations of employment status, working time and job satisfaction with sleep duration and sleep quality among the Japanese 50+ population

Abstract

Background: Few studies have captured the relationship between employment status, working time and job satisfaction and sleep duration and quality in Japan where poor sleep quality and low sleep duration are major public health concerns. Methods: We use four waves from the Japan Study of Aging and Retirement (JSTAR) to assess the relationship between employment status and self-reported job satisfaction and sleep duration and self-reported sleep quality. We control for socio-demographic characteristics, working time and self-reported measures of health. The initial sample includes 7,082 respondents. We use mixed effects modified Poisson regression for binary outcomes for sleep quality and linear mixed effects for sleep duration and multiple imputations to correct for sample attrition. Results: No major difference is observed between employment status and poor sleep quality except for housekeepers (0.123 [ 95%CI: 0.041; 0.205]) in comparison with full-time employed workers. All categories of workers tend to report sleeping longer than full-time employees with higher hours among those who retired (0.339 [95%CI: 0.218; 0.460]). Poor job satisfaction is associated with higher risks of self-reported poor sleep quality (0.230 [95%CI: 0.040, 0.421]) and waking up at night (0.362 [95%CI: 0.025, 0.699]) but the associations fade away when controlling for other health measurements (respectively, -0.137 [95%CI: -0.328, 0.054] and 0.092 [95%CI: -0.248; 0.432]). Conclusion: Retirement increases sleep duration without improving sleep quality and housekeepers sleep longer but with poorer sleep quality. Job satisfaction is a major cofounder of sleep quality among the workforce but the effect is mediated by physical and mental health levels.