Trending Clinical Topic: Shift Work

Ryan Syrek


May 07, 2021

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Two recent studies linking shift work to adverse health conditions, and another on potential risks of physical activity while at work, resulted in this week's top trending clinical topic. New data showed that working unsociable hours increased the risk for hospitalization with COVID-19 by almost threefold compared with those working regular hours (see Infographic below). Although the observational study could not establish cause and effect, one hypothesis is that working irregular hours may lead to circadian misalignment and increase susceptibility to COVID-19. The higher risks for shift workers persisted even after considering sleep duration, BMI, alcohol consumption, and smoking status.

Less job-related stress and better sleep were also recently found to significantly decrease the risk of developing COVID-19 among healthcare workers considered to be at high risk for exposure, according to new evidence. A study of 2844 frontline healthcare workers found that for each additional hour of sleep at night, risk for COVID-19 dropped by 12%. Furthermore, those who reported experiencing work-related burnout every day were 2.6 times more likely to report having COVID-19, to report having COVID-19 for a longer time, and to experience more severe COVID-19.

Beyond COVID-19, a separate study recently found that a simulated night shift schedule significantly altered the normal circadian rhythmicity of genes involved in cancer hallmark pathways. It also found that this circadian misalignment caused circadian dysregulation of genes involved in key DNA repair pathways. Researchers say the findings suggest that shift work "reduces the effectiveness of the body's DNA repair processes when they are most needed," potentially putting them at increased risk for cancer. This echoes previous findings. Last year, the World Health Organization's International Agency for Research on sCancer classified night shift work as "probably carcinogenic to humans."

Separate from schedule, physical activity performed while at work may actually increase cardiovascular risks and mortality. An observational study of more than 100,000 individuals found that higher leisure-time physical activity was associated with reduced major adverse cardiovascular events and all-cause mortality risk, whereas higher occupational physical activity was associated with increased risks, independent of each other. Researchers say the findings show the need to inform those performing manual work that their health does not benefit from those activities and that they should be physically active during leisure time. A separate study from Norway also showed a U-shaped relationship between occupational physical activity and mortality.

Many job-related health concerns have become magnified during the pandemic. The new evidence about dangers associated with shift work captured much attention this week, becoming the top trending clinical topic.

Read more about health concerns related to circadian rhythm.


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