Does night work increase risk for prostate cancer?


According to a new study in the American Journal of Epidemiology, a history of working night shifts may be associated with a large increase in risk for prostate cancer.

This new study by Parent and her colleagues at the University of Quebec used data from a population-based, case-control study carried out in Montreal, Quebec, Canada, between 1979 and 1985, which collected job histories, including work hours, from 3,137 males with incident cancer at one of 11 anatomic sites and from 512 controls.

Here are the core findings of this study:

  • Compared with men who never worked at night, the adjusted odds ratios (ORs) for the men who ever worked at night were
    • 1.76 for lung cancer
    • 2.03 for colon cancer
    • 1.74 for bladder cancer
    • 2.77 for prostate cancer
    • 2.09 for rectal cancer
    • 2.27 for pancreatic cancer
    • 2.31 for non-Hodgkin’s lymphoma
  • Equivocal evidence or no evidence was observed for several other forms of cancer.
  • There was no evidence of increasing risk with increasing duration of night work.

Parent et al. conclude that “… night work may increase cancer risk at several sites among men.”

The bottom line is that if this association can actually be demonstrated in other ways, then it may be prostate cancer that is the greatest cancer risk for men who have a history of night work. However, it is also clear that these data need to be validated in other ways before any conclusions are drawn about this potential association between night work and risk for cancer.

4 Responses

  1. Thanks for the chuckle!

  2. I am sharing this by posting it on my Facebook pages. For all I know some of my FB and physical friends do work at night. I do know that very many of them are professional writers with “day jobs.” If writing is included here, they had better watch out. Or at least wait until more is known.

  3. I think we have to assume that “work at night” implies regularly working the full night shift (e.g., 10 pm to 6 am or similar) as opposed to doing some form of additional work after one’s regular day job.

  4. Thanks Sitemaster. That is exactly what I was not sure of. I posted the abstract and got one response — from a person who does or did full nights. He wrote that it “messed [him] up.” I have no idea what he meant and it is not proper to ask.

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