Night shift work and the risk of metabolic syndrome: Findings from an 8-year hospital cohort

Abstract

Objectives Studies concerning the risk of metabolic syndrome associated with night work have shown inconsistent findings, due to imprecise working time data and cross-sectional design. We used register-based daily working time data to examine the risk of incident metabolic syndrome associated with night shift work. Methods Working time data collected between 2010 and 2018 of 5775 Taiwanese hospital workers were used to identify night shift workers and to calculate the number of night shifts. Metabolic syndrome was identified by annual occupational health examination results, which were linked to the working time data. Logistic regression models and generalized estimating equations were used to examine the association between night shift work and metabolic syndrome and the 5 components of metabolic syndrome. Results Night shift work is associated with a higher risk of developing metabolic syndrome (adjusted OR = 1.36, 95% CI = 1.04 to 1.78) and high waist circumference (adjusted OR = 1.27, 95% CI = 1.07 to 1.78) compared to day work. Among night shift workers, increased number of night shifts was associated with high blood pressure (adjusted OR = 1.15, 95% CI = 1.01 to 1.31). Conclusions Night shift work is associated with metabolic risk factors. Long-term effects of circadian rhythm disruption on metabolic disturbances needs to be further studied.

The mediating effect of sleep duration on metabolic syndrome severity in adults: a structural equation modeling approach

“…A study involving Malaysian manufacturing workers identified night shift work as a significant risk factor for MetS [ 10 ]. Research on Taiwanese hospital employees and railway workers in southwest China indicated that long-term shift work, particularly, heightened the risk of developing MetS [ 29 , 30 ]. A meta-analysis conducted in 2021 also indicated a positive correlation between shift work and the risk of MetS, which remained significant regardless of adjusting for sleep duration [ 31 ].…”

Different levels of circadian (de)synchrony ­– where does it hurt?

“…Shift workers commonly have inefficient and poor quality sleep causing fatigue ( Paech et al , 2010 ). Moreover, forced activity and sleep deprivation in the normal rest phase strongly impacts the immune system ( Irwin et al , 2006 ), and shift workers are more likely to develop chronic medical conditions like cardiovascular diseases ( Ha and Park, 2005 ), metabolic syndrome ( Cheng et al , 2021 ), psychological disorders (reviewed by Cheng & Drake, 2018 ) and others. Simulations of shift work and abnormal LD cycles in laboratory settings are used to investigate the mechanisms of chronodisruption and will be described in detail in the next sections.…”

Different levels of circadian (de)synchrony ­– where does it hurt?

“…Shift workers commonly have inefficient and poor quality sleep causing fatigue (Paech et al, 2010). Moreover, forced activity and sleep deprivation in the normal rest phase strongly impacts the immune system (Irwin et al, 2006), and shift workers are more likely to develop chronic medical conditions like cardiovascular diseases (Ha and Park, 2005), metabolic syndrome (Cheng et al, 2021), psychological disorders (reviewed by P. Cheng & Drake, 2018) and others. Simulations of shift work and abnormal LD cycles in laboratory settings are used to investigate the mechanisms of chronodisruption and will be described in detail in the next sections.…”