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Published: May, 2007; Vol 3, Num 12

 

BMI and Prostate Cancer:

Obesity Propels Prostate Cancer Mortality

Despite an odd twist, a new study shows that being overweight or obese increases the chances that a man who develops prostate cancer will die from it.

That conclusion was drawn from a lengthy National Cancer Institute study of more than 285,000 men that checked their body mass index (BMI) – the ratio of weight to height – against the development of prostate cancer after five years and prostate cancer death after six.  (A BMI of 25 or less is considered normal, 25 to 30 is overweight and above 30 is obese.)

Oddly, men with a BMI of 40 or more (severely obese) had a 33 percent less chance of developing prostate cancer than those in the normal range.  In contrast, however, being even the least bit overweight increased the chances of death when prostate cancer developed.  The chances were 25 percent greater for those with BMIs between 25 and 30, 46 percent greater for those between 30 and 35 and more than double for those above 35.

The study also found a significant association between weight gain during the five-year interval and mortality (death) among those who developed prostate cancer.

In another study (also in the journal Cancer), researchers found that among men who were newly diagnosed with prostate cancer, those who were obese a year before the diagnosis were 2.6 times more likely to die from the cancer than men who were of normal weight. 

The studies did not offer an explanation for the associations between BMI and the development or mortality of prostate cancer, but other studies suggest that hormonal factors in prostate cancer development, in combination with age and family history, may explain why weight plays different roles in different people.  Hormonal factors are known to influence weight gain in some people.

Unlike many other cancers, the overall survival rate for prostate cancer is high because the disease is usually slow growing, can be detected early and can be successfully treated.

Nevertheless, prevention is better than treatment.  Despite the twist in the data, no one advocates that men put on extra pounds as a protection against prostate cancer.  Indeed, the medical profession is unanimous in urging men (and women, too) to lose weight and improve their fitness.  “The growing prevalence of obesity in Western countries is alarming,” said Dr. Margaret E. Wright, who led the National Cancer Institute study, “and reducing the risk of prostate cancer death is only one among many health reasons to maintain a healthy weight through diet and exercise.”

To help LIUNA members understand the danger, the LHSFNA publishes a short brochure: What Laborers Should Know about Prostate Cancer.  It is available through the Fund’s online Publications Catalogue.

[Steve Clark]