SHIFT work and respiratory infections may be linked partly through poorer sleep quality among healthcare workers.
A prospective cohort study involving 396 hospital employees found that shift workers had a 23% higher incidence rate of influenza-like illness and acute respiratory infection episodes than non-shift workers. Researchers examined whether sleep, physical activity, and diet could help explain this association.
Participants included healthcare workers who either worked rotating or night shifts or had not worked either type of shift for at least six months. At baseline, sleep duration and physical activity were assessed using accelerometers and diaries, while participants reported sleep quality and recorded their food intake.
Over the following six months, participants used a smartphone application to report respiratory symptoms daily. Shift workers averaged 3.5 influenza-like illness or acute respiratory infection episodes compared with 2.9 among non-shift workers.
After adjustment for age, gender, occupation, influenza vaccination status, and perceived general health, shift workers had a 23% higher incidence rate of respiratory infection episodes than non-shift workers.
When sleep, physical activity, and dietary measures were incorporated into the model, the difference fell to 15% and was no longer statistically significant.
Poor sleep quality produced the largest indirect effect. Shift workers had more than three times the odds of reporting poor sleep quality compared with non-shift workers.
Through the pathway of poorer sleep quality, shift workers had a 29% higher incidence rate of influenza-like illness and acute respiratory infection episodes.
Notably, perceived sleep quality appeared more important than objectively measured sleep duration. Shift workers were more likely to experience frequent short sleep, but neither short nor long sleep duration significantly mediated the relationship between shift work and respiratory infections.
Physical activity and eating patterns also did not emerge as significant mediators. Although shift workers were substantially more physically active at work, neither workplace nor leisure activity explained the higher infection incidence. The number of meals and snacks consumed each day also had no significant mediating effect.
The findings suggest perceived sleep quality may warrant greater attention when investigating infection susceptibility among healthcare shift workers. However, the researchers emphasized that further studies are needed to replicate the findings, evaluate additional mechanisms, and determine whether improving sleep quality can influence respiratory infection incidence.
Reference
Loef B et al. The mediating role of sleep, physical activity, and diet in the association between shift work and respiratory infections. Scand J Work Environ Health. 2020;46(5):516-524.
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