Wednesday, December 27, 2006

Weight Loss Decreases your Risk of Aggressive Prostate Cancer

This month's Cancer Epidemiology Biomarkers and Prevention journal has a fascinating study on the effect of weight loss on the development of prostate cancer (Full-text free here).

Author Carmen Rodriguez and colleagues were curious to see whether or not weight loss affected the risk of prostate cancer.

Seven of nine prior prospective studies had demonstrated that increased weight was associated not with increased risks of prostate cancer overall, but rather increased risk of aggressive prostate cancer and prostate cancer mortality.

The study population started with the 86,404 male participants of the Cancer Prevention Study II Nutrition Cohort followed by the American Cancer Society since 1992.

In a methodology too rarely seen in weight loss studies, the authors chose to exclude the first 2 years of followup (1992-1994) for their 11 year study due to the fact that many diseases lead to weight loss, and should initial weight loss be unintentional and due to an as yet diagnosed serious illness, the results from those individuals would negatively skew the results of the study. This type of lead-in bias in studies including weight as a variable has certainly tainted the results of the many of them that did not include a first-few years weight loss exclusion criteria.

The results were rather striking.

Firstly the risk of low-grade (less aggressive) prostate cancer actually decreased significantly with increasing weight! In contrast however, the risk of high grade (more aggressive) prostate increased with increasing weight, as did the risk of metastatic spread from the prostate and prostate cancer mortality.

(For the authors comments as to some possible biological explanations for these trends, read their clear discussion in their paper)

In terms of weight loss, men who lost 11 or more pounds between 1982 and 1992 had a 40% lower risk of developing aggressive prostate cancer!

That weight increases your risk of developing cancer has certainly been established beyond any significant shadows of doubt in multiple prior studies. What's so exciting about this study is that it's now the second study that has specifically identified intentional weight loss as a means to decrease your risk of cancer (the first demonstrating that women who lost 22lbs had a 60% decrease in their risk of developing breast cancer, published in 2006 in JAMA).

11 pounds is certainly not 100!

Truly even small amounts of weight loss can lead to dramatic affects on your health.

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2 comments:

  1. Anonymous1:02 pm

    Or you could gain 21 pounds and see the same (supposed) reduction in prostate cancer risk!

    For a more complete perspective on this study:

    http://junkfoodscience.blogspot.com/2006/12/fabled-links-between-weight-and.html

    ReplyDelete
  2. Actually, that's a very disingenuous comment.

    As noted in the post and in the paper, increased body weight does decrease the risk of less aggressive prostate cancers.

    As noted by the link you've supplied, "Even risks for metastatic and the non-metastatic high grade cancers did not increase with increasing body weights." and that's true, but spun which is an interesting thing for a blog that seems to spend a great deal of effort and vitriol talking about the spins that it doesn't like.

    The spin is the fact that the risk of non-metastatic high grade cancers diminished significantly with weight loss of 11-20lbs in this study. A much greater risk reduction than that slight and non-statistically significant reduction found with weight gain.

    I would also note that the link you provided is to a blog that does not allow for comments.

    A shame.

    ReplyDelete