A new study published in the journal Current Biology indicates that people working in shifts are more likely to develop cancer. Even though some shift workers might say that working outside normal hours can have some benefits such as more time for childcare this study indicates that working outside the usual nine to five hours can have severe health consequences since the human body is disturbed from its natural cycle of walking during day time and sleeping at night.
For the study researchers from Erasmus University Medical Center conducted an experiment on mice which were subjected to a schedule similar to the one of shift workers. The animals used in the study had a gene equivalent to the human BRCA gene which can noticeably increase the risk of developing breast cancer.
The findings of the study indicate that unlike the typical cancer-prone mice, the ones who were on a shift work schedule showed signs of cancer eight weeks earlier. In addition they also gained around 20 percent more weight compared to the other mice.
The biological cycles of 24 hours which both humans and mice function on are called circadian rhythms. Not only this study, but previous studies as well, show that circadian disruptions like shift working can be harmful for health. Studying this phenomenon in humans can be challenging since there are many factors in an individual’s life which can influence one’s health.
Shift work is something often met in important professions such as police, transportation, health care and firefighters. The lead author of the study Bert van der Horst from Erasmus University Medical Center explained that in a real-life situation their experiment imitated a 12-hour difference which a flight attendant flying from New York to Hong Kong would experience.
Mimicking such a situation in a controlled setting using mice is a good way to observe certain factors which should be taken into account when studying humans even though they are more complex. There are however some similarities which can be found between humans and mice. Bert van der Horst remarked:
“We have shown that this mouse model so well translates to the human situation. We can now start to explore in detail which factors in shift work are causing the increased cancer vulnerability and how to counteract them with well-designed intervention strategies, which subsequently can be validated in well-designed human studies.”
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