Sleep, work and ill health, part 3

Part 3: the effects of shiftwork on health

Summary:

In the third of our occasional series on the occupational implications of sleep disorders, occupational physician Roger Cooke reviews the relationship between shiftwork and ill health.

A review by the International Labour Organization in 2003 found strong evidence that night work was associated with cardiovascular and gastrointestinal disorders, and some evidence for a link with reproductive disorders, and concluded that night work increases the risk of health disorders^1. In 2007, the International Agency for Research on Cancer (IARC) used the definition of ‘shiftwork that causes circadian disruption’ and concluded that shiftwork with a large component of night work is a probable human carcinogen². This conclusion was confirmed at an IARC meeting in June 2019, at which night shiftwork was classified in Group 2A – ‘probably carcinogenic to humans’, reflecting limited evidence in humans, sufficient evidence of cancer in experimental animals, and strong mechanistic evidence in experimental animals. However, while the possibility of such a relationship has attracted understandable attention, some epidemiological studies have been open to criticism, reflecting in particular the lack of a universally accepted definition of shiftwork.

 

Roger Cooke is a consultant in occupational medicine and honorary senior lecturer at the Institute of Occupational and Environmental Medicine at the University of Birmingham.

 

Author: Cooke R

Tags cancer cardiovascular shiftwork sleep

Occupational Health at Work February/March 2020 (vol. 16/5) pp26-30

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