IARC Retains “Probably Carcinogenic” Classification for Night Shift Work

IARC Retains “Probably Carcinogenic” Classification for Night Shift Work

News from ISGlobal

The International Agency for Research on Cancer (IARC) has just published its decision to maintain the classification of night shift work as being “probably carcinogenic to humans” (Group 2A). The IARC classifies agents into four risk categories on the basis of the strength of the evidence on whether the substance or agent causes cancer. Group 2A is the second highest category in terms of the level of certainty of the evidence.

This is the second time the IARC has evaluated the carcinogenicity of night shift work. The new evaluation was undertaken by a group of 27 experts from 16 countries, including ISGlobal researcher Manolis Kogevinas, who also chaired the Epidemiology working group.

The evidence currently available in the literature suggests that disruption of the circadian rhythm is associated with breast and prostate cancers; and also that the association between night shift work and cancer is mediated not just by changes in melatonin production but also by disruptions affecting other hormones, such as testosterone.



IARC Monographs Vol 124 group. Carcinogenicity of night shift work. The Lancet Oncology. July 04, 2019

International Agency for Research on Cancer. Volume 124: night shift work. IARC Working Group. Lyon, France; June 4–11, 2019. IARC Monogr Eval Carcinog Risk Chem Hum (in press).


More information:
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