One common working habit has been consistently associated with cancer and is classified by the World Health Organisation as a "possible carcinogenic."
Night shift work, or work during the hours people would usually be sleeping, has been classified as a "possible carcinogenic" by the World Health Organisation. The classification was given after multiple studies over a number of years consistently associating the disruption of sleeping patterns with cancer.
One report published in 2019 by the International Agency for Research on Cancer (IARC), a part of the World Health Organisation, concluded that night shift work is "probably carcinogenic to humans." The reason given was that night shift work disturbs the body's 24-hour circadian (or daily) rhythms, responsible for our sleep-wake cycle among other bodily functions.
