Does smoking history predict PSA levels in a clinically significant manner?

A new paper published on line in the Journal of Urology suggests that the PSA and %free PSA levels of current smokers and former smokers may be statistically significantly impacted compared to those of men who have very rarely or never smoked.

Li et al. were able to examine data from 3,820 men, all aged 40 years or older, who had previously participated in the National Health and Nutrition Examination Survey (NHANES) between 2001 and 2006.

The men were divided into three groups:

  • Men with serum cotinine levels > 10 ng/ml or who had smoked at least 100 cigarettes during their lifetime and, at the time of interview, reported smoking every day or some days (“current smokers”)
  • Men with serum cotidine levels < 10 ng/ml who had smoked at least 100 cigarettes during their lifetime and who responded “not at all” to the question about whether they smoked now, at the time of their interview, were classified as (“former smokers”)
  • Men with a serum cotidine level < 10 ng/ml who stated that they had smoked fewer than 100 cigarettes in their lifetime (“never smokers”)

Note that a serum cotidine level of > 10 ng/ml is associated with active smoking within the immediately preceding few days.

The core findings of this study were that:

  • For all ages and all patients combined
    • The average (median) total PSA level was 0.90 ng/ml (range, 0.81–0.90 ng/ml).
    • The median free PSA level was 0.26 ng/ml (range, 0.25–0.28 ng/ml).
  • For all “current smokers” (n= 1,188)
    • The median total PSA level was 0.80 ng/ml (range, 0.80–0.90 ng/ml).
    • The median free PSA level was 0.24 ng/ml (range, 0.23–0.25 ng/ml)
  • For all “former smokers” (n= 1,359)
    • The median total PSA level was 0.95 ng/ml (range, 0.83–1.01 ng/ml).
    • The median free PSA level was 0.28 ng/ml (range, 0.27–0.30 ng/ml).
  • For all “never smokers” (n= 1,270)
    • The median total PSA level was 0.9o ng/ml (range, 0.80–0.94 ng/ml).
    • The median free PSA level was 0.27 ng/ml (range, 0.25–0.29 ng/ml).
  •  Multivariate linear regression analysis showed that, compared to “never smokers,”
    • The median total PSA level was 7.9 percent lower among “current smokers”
    • The median total PSA level was 12.2 percent lower among “former smokers.”
  • 34.2 percent of all participants had a %free PSA level of < 25 percent.
  • “Current smokers” had a significantly lower %free PSA level than former smokers.
  • High body mass index and a diagnosis of diabetes were also significantly associated with a lower total PSA level.

Exactly what impact such data may have on the interpretation of PSA levels and the need for a man to have a biopsy cannot be determined on the basis of a single study like this. It would be interesting to know if a larger, prospective study could give greater insight into any association between smoking, PSA level, and risk for diagnosis with relatively indolent or clinically significant forms of prostate cancer. It should be noted that an 8 to 10 percent drop in PSA level is small (say from 4.0o ng/ml to 3.6 ng/ml). It is hard to believe that the clinical significance of such a change in value could be accurately determined in a specific individual on the basis of a single PSA test result — or that it would be likely to make much difference to whether a primary care physician did or did not refer the patient to a urologist for further work-up.

2 Responses

  1. Interesting data but it does not take into effect the dietary impact of smokers versus non-smokers. I had many family members, mostly male, but some females, and they all seem to have eating habits that matched their bad habit of smoking.

    Non-smokers seem to care more about their health, and therefore eat healthier foods. The effect of smoking will very soon become apparent in Asia where men have the lowest rate of prostate cancer in the entire world, but are now avid smokers, especially the men in China of the new “Chuppie” generation.

  2. I am a final-year student of medical laboratory science at Nnamdi Azikiwe University, Nnewi campus, Anambra, Nigeria. I recently carried out my final-year project work on “The assessment of prostate specific antigen levels in adult male smokers in Nnwei, Nigeria”, soon to be published on the internet once my academic supervisor has taken a final look at the work.

    From my data obtained during this research I noticed a significant decrease in the PSA levels of smokers when compared with non-smokers of corresponding ages and so I totally agree with the data reported above.

    There were, of course, many limitations to my study: limited resources, lack of time (based on my school program), unwillingness of prospective subjects (although the few that participated were “chronic chain smokers”), narrowness of my study (not taking into consideration their nutritional state at the time of study as Richard had already pointed out, for example their zinc levels, eating habits, etc.) and so on. Maybe very soon, by God’s special grace, I would love to be able to re-do this study with more willing and available subjects and a controlled research environment.

    Really love your work and some day would be honored to work with you.


    PS: I was wondering if you know any research team or club I can join because I really love research work.

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