Two New European Studies Confirm Hazards Related to Shift Work


Two new studies have examined—and again confirmed—the health and cognitive hazards faced by workers who do so-called “shift” work, such as working nights or rotating shifts.

One study by ANSES, the French Agency for Food, Environmental and Occupational Health & Safety, assessed the health risks for workers due to atypical working hours, in particular night work, whether regular or irregular.

The expert appraisal confirmed the health risks associated with night work due to the disruption of their biological or circadian rhythms. The assessment concluded that:

  • The effects on drowsiness, the quality of sleep and the reduction of total sleep time, and metabolic syndrome are proven
  • The effects on psychological health, cognitive performance, obesity and weight gain, type 2 diabetes and coronary heart diseases are probable
  • The effects on dyslipidaemias (excessive concentrations of certain lipids in the blood), high blood pressure and ischemic stroke, are possible
  • Regarding cancer, the study found that there’s a probable effect of night work on the risk of cancer, in particular, breast cancer.

The study also shows that the frequency and severity of incidents occurring during night work are generally higher.

In the second study by researchers from Uppsala University in Sweden, shift workers, compared to non-shift workers, needed more time to complete a test that’s frequently used by doctors to screen for cognitive impairment.

But those who had quit shift work more than five years ago completed the test just as quick as the non-shift workers, which suggests that it may take at least five years for previous shift workers to recover brain functions that are relevant to the performance on this test.

Other studies have also looked at the hazards related to shift work, including:

One way to eliminate or reduce some of the impacts of shift work on workers is through a fatigue risk management system, including a Model Fatigue Management Policy.