You now, finally, have a legitimate reason for avoiding night shifts, and it’s not just the lack of power. The International Agency for Research on Cancer (IARC)  conducted an evaluation of night shift work. The evaluation was carried out by a Working Group of 27 independent international experts from 16 countries. The experts reviewed all relevant studies in the publicly available scientific literature on night shift work- work that involves circadian disruption.

The conclusion of the group was that night shifts are probably carcinogenic to humans, and classifies it as Group 2A. This classification is about hazard identification and relates to the ‘level of certainty that an agent can cause cancer.’

Category Group 2A is used when there is limited evidence of carcinogenicity in humans and sufficient evidence of carcinogenicity in experimental animals. Limited evidence means that a positive association has been observed between exposure to the agent and cancer but that other explanations for the observations could not be ruled out.

For comparison, IARC classification of radiofrequency electromagnetic fields is only 2B, meaning that there could be some risk, and therefore we need to keep a close watch for a link between cell phones and cancer risk.

This is probably a surprising result for most of you, but it also proves an important point- Hysteria is not always justified, and health risks might lie where you least expect them.