In recent weeks a number of studies have confirmed the conclusions of older research about the increased risks of cancer for workers who carry out night or shift work.

Researchers in Sichuan University (China) reviewed 61 studies published between 1996 and 2017 on the effects of night work on the health of women. The data cover 115 000 cases of cancer and 4 million participants living in the US, Australia, Asia and Europe. They conclude that in the long term the risk of breast cancer increases by 32 %, skin cancer by 41 % and gastrointestinal cancers by 18 %.

The risk of breast cancer increases by 3.3 % for every five years of night work.

Of all the occupations studied, nurses are most affected: they are 58 % more likely to get breast cancer, 35 % more likely to get a gastrointestinal cancer (stomach, oesophageal, liver, pancreatic, colorectal) and 28 % more likely to get lung cancer.

This research was published at the start of January in the journal Cancer Epidemiology, Biomarkers and Prevention.

Atypical working hours are also harmful to men's health. In September 2017 a study published in The Scandinavian Journal of Work Environment & Health revealed that workers carrying out shift or night work have a higher risk of contracting prostate cancer. According to the research, this risk is twice as high for them as for workers who have never worked shifts or at night. Men who have worked shift or night work for more than 20 years are three or four times more likely to get prostate cancer.

The sectors with the highest risks are metalworking (metal cutting, metal forming, foundry work), mining, and mechanical and production engineering.

The researchers carried out a cohort study of 1 757 men in the highly industrialised Ruhr region.

More information:

Xia Yuan, et al., Night Shift Work Increases the Risks of Multiple Primary Cancers in Women: A Systematic Review and Meta-analysis of 61 Articles, Cancer Epidemiol Biomarkers Prev., January 2018. Abstract

Behrens T., et al., Shift work and the incidence of prostate cancer: a 10-year follow-up of a German population-based cohort study, Scand J Work Environ Health, September 2017. Abstract