Night work has long been known to be detrimental to health, with links to obesity and diabetes. Now, a new metastudy has classified night work as a probable carcinogen, placing it in the same category as glyphosate, the herbicide. The study was conducted by the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO). The IARC had already classified night work as “probably carcinogenic to humans” in 2007, but the new study, which analyzed 27 studies from 16 countries, has strengthened the evidence.
The human body is regulated by an internal clock that is synchronized by genes and external factors such as daylight. Deviating from this natural rhythm, as around 20% of the working population in Germany do, has long been known to cause health problems. The IARC study investigated whether night work could cause cancer, and found that there is a “relatively clear association” between night work and breast, prostate, and colon cancer. However, the methodology of the study did not allow for other causes to be completely ruled out, so the IARC has classified night work as a probable carcinogen, on the same level as red meat and glyphosate.
The study does not provide exact figures on the risk of cancer from night work, but it does show that under certain conditions, night work can cause cancer. The IARC has not yet made any recommendations to policymakers or affected individuals, as it is still not possible to make definitive statements about the likelihood of developing cancer due to night work. Nevertheless, the study provides further evidence of the dangers of night work, and highlights the need for measures to protect workers who are required to work at night.
