Sleep disturbance-related depressive symptom and brain volume reduction in shift-working nurses

Abstract

Disturbed sleep is the most common effect of shift work. A large corpus of research indicates an association between sleep disturbance and depressive symptom in shift workers. In this study, we proposed the mediating role of grey matter (GM) structure in the relationship between sleep disturbance and depressive symptom. We collected structural MRI (sMRI) data as well as assessing the level of sleep disturbance and depressive symptom with the Pittsburgh Sleep disturbance Index and Zung Self-Rating Depression Scale, respectively, in 20 shift-working nurses and 19 day-working nurses. The shift-working nurses reported greater severity of sleep disturbance and depressive symptom, and furthermore, they exhibited reduced GM volume in the left postcentral gyrus (PostCG), right PostCG, right paracentral lobule, and left superior temporal gyrus (STG), compared to the day-working nurses. For each of the four brain regions, we formulated a mediation hypothesis by developing a mediation model that represents a causal chain between GM volume, sleep disturbance, and depressive symptom. Tests of the hypothesis on the mediation of GM volume revealed that inter-individual variations in left PostCG volume and left STG volume accounted for the influence of sleep disturbance on depressive symptom. These results suggest that structural alterations in PostCG and STG play an intervening role in the development of depressive symptom following sleep disturbance. We propose the need of considering neuroanatomical abnormalities in explaining and understanding symptomatic changes induced by sleep disturbance.

Keep Your Mask On: The Benefits of Masking for Behavior and the Contributions of Aging and Disease on Dysfunctional Masking Pathways

“…When this is done, the circadian system is unable to fully adjust to the shift work, and therefore humans are only able to stay awake at night because the masking system is overriding the endogenous circadian rhythm that is misaligned with behavior ( Vokac et al, 1981 ). Nurses that engage in many years of shift work have been shown to be at a higher risk of developing breast cancer ( Szkiela et al, 2020 ), depression ( Booker et al, 2020 ; Park et al, 2020 ), and anxiety ( Booker et al, 2020 ). Animal models of shift work with nocturnal mice have also revealed the deleterious effects of misaligning circadian rhythms and behavior which occurs due to effects of masking, but that these effects are most severe when the organism is expected to flip-flop their behavior on days of work vs. days of rest, also known as “circadian desynchrony” ( Barclay et al, 2012 ).…”

Cortical thickness and sub-cortical volumes in post-H1N1 narcolepsy type 1: A brain-wide MRI case-control study

“…Compared to day-workers reduced STG volume has been reported among shift workers who also reported more sleep disturbances and depressive symptoms. [43] Further, thinner STG has also been reported in patients with obstructive sleep apnea (OSA). [44] In our study, five NT1 patients had AHI ≥ 5, however these patients were excluded from the sensitivity analysis which largely supported the results from the main analysis.…”

Bipolar spectrum disorders among American registered nurses: a narrative literature review

“…Written informed consent from all participants was obtained in accordance with the Declaration of Helsinki and its later amendments. The study was approved by the Institutional Review Board at the Seoul St. Mary's Hospital, Seoul, Korea [24].…”

“…It is well-established that alterations in circadian rhythm are a primary risk factor for symptom development in individuals with BSDs, along with other deleterious effects on metabolic and cardiovascular health [21][22][23]. Park et al [24] discovered structural changes in the brains of shift-working nurses compared to those who worked days. The authors found decreased volume in the post-central gyrus, right paracentral lobule, and left superior temporal gyrus.…”