Twenty-four-hour shift work, depressive symptoms, and job dissatisfaction among Japanese firefighters

The influence of a 24-hr shift-work burden on firefighters' mental health has not been fully investigated. The purpose of this study is to clarify the relationships between specific workload items among firefighters engaged in 24-hr shift work and job stress as estimated by the generic job-stress questionnaire on depressive symptoms and job dissatisfaction from the National Institute for Occupational Safety and Health (NIOSH).

The subjects were 1,301 firefighters. The questionnaire covered age, gender, job type, job class, marital status, smoking and drinking habits, number of attendances, turnout time, extra work hours, average nap-time, the Center for Epidemiologic Studies Depression Scale (CES-D), and questions from the NIOSH generic job-stress questionnaire, including those on job satisfaction.

In multivariate logistic regression analyses, a model that included all variables except the measures from the NIOSH generic job-stress questionnaire showed that shorter nap-time had significant higher odds ratios (ORs) for depressive symptoms and job dissatisfaction, but the significances disappeared in a fully adjusted model. In fully adjusted logistic regression analyses, low quantitative workload, low variance in workload, high intra- and intergroup conflict, low social support from a supervisor, high role conflict and ambiguity, and low self-esteem had significant higher ORs for depressive symptoms and/or job dissatisfaction.

Amount of workload, variance in workload, intra- and intergroup conflict, social support from a supervisor, role conflict and ambiguity, and self-esteem were significantly related to depressive symptoms and/or job dissatisfaction among Japanese firefighters. Moreover, inadequate nap-time may affect their mental health.