Association between depressive symptoms and morningness-eveningness, sleep duration and rotating shift work in Japanese nurses

Abstract

Higher depressive symptoms have been reported in rotating shift workers compared with day workers. Depressive symptoms in adults who do not engage in night work have also been shown to be associated with chronotype and sleep duration. This study examines associations between depressive symptoms, morningness-eveningness (i.e. the degree to which people prefer to be active in the morning or the evening), sleep duration and rotating shift work. Japanese nurses (1252 day workers and 1780 rotating shift workers, aged 20-59) were studied using a self-administered questionnaire. The questionnaire covered depressive symptoms, morningness-eveningness, sleep habits and demographic characteristics of the participants. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to determine the levels of depressive symptoms. A Japanese version of the Morningness-Eveningness Questionnaire (MEQ) was used to measure morningness-eveningness. The CES-D score of shift workers was significantly (p < 0.05) higher than that of day workers. The MEQ score was significantly (p < 0.05) lower (i.e. greater eveningness) in shift workers than in day workers. Sleep duration on the day shift was significantly (p < 0.05) shorter in shift workers than in day workers. Simple linear regression revealed that the MEQ score, sleep duration on the day shift and current work shift (i.e. rotating shift work) were significantly (p < 0.05) associated with the CES-D score. Multivariate linear regression indicated that greater eveningness and shorter sleep duration were independently associated with higher CES-D scores, while rotating shift work was not. These associations between the MEQ score, the sleep duration and the CES-D score were also confirmed in both day workers and shift workers when the groups were analyzed separately. These results suggest that greater eveningness and shorter sleep duration on the day shift were independently associated with higher levels of depressive symptoms, which may explain associations between rotating shift workers and depressive symptoms. These findings have important implications for the development of novel strategies for preventing poor mental health in day workers and rotating shift workers.

The relationship between sleep pattern and depression in Chinese shift workers: A mediating role of emotional exhaustion

“…In other words, workers with an evening-type sleep pattern had higher levels of depression than those with morning-types, which supports previous research in this area (Chen, 2007;Kim et al, 2010;Togo et al, 2017). First, we found that sleep pattern was negatively associated with depression.…”

“…Therefore, it is crucial to consider the negative impact of sleep pattern on depression and to find out the factors associated with it, which may provide a key target for alleviating depression in this group. Those identifying as evening types have been shown to experience more depressive symptoms than morning types, which might be because evening types have shorter sleep duration or worse sleep quality than morning types, which may, in turn, induce mood disturbance (Sullivan & Martin, 2016;Yoshizaki, & Komatsu, 2017). Our research hypothesizes that the sleep pattern of three shifts employees in China will be correlated with depression levels.…”

“…Morning types prefer to go to bed and wake up early (e.g., sleep during the hours of 10 p.m.-6 a.m.), performing better in physical or intellectual activities in the day, while evening types prefer later bedtimes and later wake times (e.g., sleep during the hours of 12 p.m.-8 a.m.), performing greater in the evening or night. Thus, while previous studies have shown that sleep pattern is associated with depression (Abe et al, 2011;DAĞ & Kutlu, 2017;Kanno, Tsugawa, & Yoda, 2014;Kitabatake & Nagamatsu, 2010;Togo, Yoshizaki, & Komatsu, 2017), there is a lack of research on the relationship between sleep pattern and depression in shift workers, and specifically within three shifts staff in China. To date, research investigating sleep patterns has mostly concentrated on children and adolescents, given that sleep is known to play an important role in the development of children's growth, cognition, emotion and behaviour, as well as immune system regulation (Hsiao et al, 2015).…”

“…The majority of the population falls between these two extremes (Riedy et al, 2017). Those identifying as evening types have been shown to experience more depressive symptoms than morning types, which might be because evening types have shorter sleep duration or worse sleep quality than morning types, which may, in turn, induce mood disturbance (Sullivan & Martin, 2016;Yoshizaki, & Komatsu, 2017). However, sleep pattern also has an important influence on adult wellbeing and function with those exhibiting an eveningtype pattern particularly at risk of lower wellbeing (Gulec et al, 2013).…”

“…However, Arana-Lechuga et al (2008) found that children's depression also varied with sleep pattern. Thus, while previous studies have shown that sleep pattern is associated with depression (Abe et al, 2011;DAĞ & Kutlu, 2017;Kanno, Tsugawa, & Yoda, 2014;Kitabatake & Nagamatsu, 2010;Togo, Yoshizaki, & Komatsu, 2017), there is a lack of research on the relationship between sleep pattern and depression in shift workers, and specifically within three shifts staff in China. Therefore, it is crucial to consider the negative impact of sleep pattern on depression and to find out the factors associated with it, which may provide a key target for alleviating depression in this group.…”