Shift-work, night-work, and risk for prostate cancer


Yet another study (this one from Germany) has shown a strong association between shift-work and night-work and risk for diagnosis with prostate cancer.

The new study by Behrens et al. is based on data from the Heinz Nixdorf Recall Study among the same large group of men, who completed baseline surveys in 200o to 2003 and then repeat surveys in 2011 to 2014. All study participants were residents of the highly industrialized Ruhr area in Germany.

This particular set of data is based on 1,757 men who did not report a history of prostate cancer at baseline.

Behrens et al. found that, among these 1,757 men, compared to those men who were never involved in  either shift- or night-work, they observed:

  • A significant increase in risk for diagnosis with incident prostate cancer among the men who were ever employed in shift-work (hazard ratio [HR] = 2.29)
  • A significant increase in risk for diagnosis with incident prostate cancer among the men who were ever employed in night-work (HR = 2.27)
  • A steady increase in risk for diagnosis with incident prostate cancer with duration of employment in shift- and night-work
  • Strongly elevated risk for diagnosis with incident prostate cancer among subjects with early sleep preference (although this analysis were limited by a relatively small number of cases).

This is far from being the first time that studies have shown an association between shift- and night-work and increased risk for diagnosis with prostate cancer.

2 Responses

  1. I have worked evening and night shifts and combinations for some years … this article, at least somewhat, gives me an “answer” for the “possible” “cause” of it. Family history is negative.

    But when reading the other listed articles listed below the posting, I read that back in 2015, utilizing a larger pool, there was no significant difference if working night/evening shifts.

    While a paper dated 2013 does indicate a difference and alludes to that the diagnosis is low- or very low-risk prostrate cancer. The InfoLink mentions that getting the blood drawn early morning versus later on in the day — PSA values rise and fall daily implication / fact. And goes on to mention “related factors”.

    Since I fell into the above category “low risk” determined by the numbers and biopsy and I had had a vasectomy in previous years (not many) and reading this site for the past years, I am still grappling with the course of treatment (radiation) if when a second PSA was drawn after radiation, the first was 4.01 which started the process and one was not drawn before radiation, which became interesting after treatment (no base line).

    Some related factors that I came across were different blood tubes, different labs and if sexually active before the blood testing, and of course the vasectomy issue will affect the value. Now if the gland is removed or destroyed, over time, am told the value will fall, so I keep track of the lab values and remain quiet 4 days before my blood is drawn and looking back see that my blood was drawn late morning, ruling out (?) the daily difference. The “bounce”/spike was explained = “it is in your blood” but if the factory is shut down or fading, how can the product, since this is the only source of production, cause the bounce on my 6-month blood draw? (which is dropping off “nicely”).

    The sitemaster mentions related factors and am wondering what those factors these might be … especially since the “factory” is dwindling away?

  2. Dear Richard:

    (1) The fact that there is an association between “shift-work” and “night-work” and diagnosis with prostate cancer is not “proof” that these types of work actually cause prostate cancer — but the study above does tend to suggest a strong possibility that this might be the case. Actually being able to prove this one way or the other would be extraordinarily difficult.

    (2) The PSA test is a very poor indicator of risk for prostate cancer, and — on an individual basis — precise PSA levels before and after radiation therapy are not very good when it comes to the future prognosis for any one particular patient. PSA doubling times are a much better way to use PSA data when it comes to risk for progression over time. Consequently, also, it would actually be relatively unusual for any patient to have a PSA test taken immediately before initiation of radiation therapy (as a baseline). The baseline that is used is the PSA value at diagnosis.

    (3) “Related factors” are so many that it would be impossible to list them all. They might include things as diverse as: fluid intake, alcohol consumption, diet, exercise levels, you name it! We know it includes things like use of finasteride (Proscar) and dutasteride (Avodart) and other prescription drugs.

    As far as I am aware, no one has ever done a careful, systematic, and rigorous analysis of all of the things that might impact PSA levels in patients over time and the degree to which these might be of any clinical significance. It would need hundreds of patients with highly detailed records and testing every 3 months over a period of several years.

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