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Too manly men at higher risk for prostate cancer?

By David Liu, PHD

Sunday July 29, 2012 (foodconsumer.org) -- Men who have high levels of a male reproductive hormone called testosterone are at high risk for prostate cancer and lung cancer, according to a study published on July 24, 2012 in Cancer Epidemiology, Biomarkers & Prevention.

The study led by Zoe Hyde of University of Western Australia in Australia and colleagues found each one SD increase in free testosterone was correlated with 9 percent increased prostate cancer.

The study involved 3,635 community-dwelling men aged 70 to 88 years whose blood samples were analysed to measure testosterone, sex hormone-binding globulin (SHBG), and luteinizing hormone (LH).  During a mean 6.8-year follow-up, 297, 104 and 82 cases of prostate cancer, colorectal cancer and lung cancer respectively were recorded.

In addition to the positive link between free testosterone and risk of prostate cancer, higher total testosterone was also found associated with lung cancer. 

To be exact, men who had 20 nmol/L of total testosterone were 38 percent more likely than those who had 15 nmol/L to develop lung cancer. Men who had 30 nmol/L were 3.6 times more likely than those who had 10 nmol/L to develop the disease.  Higher free testosterone was associated with lung cancer too.

However, no hormones tested for the study were correlated with colorectal cancer and SHBG and LH were not linked to lung cancer either.

All associations held true after current smokers were excluded from the analysis.

The researchers concluded "Higher free testosterone was associated with incident prostate cancer. Higher testosterone levels may also be associated with lung cancer."

They suggested that research need to be done to examine whether testosterone therapy would increase risk of prostate cancer.

Prostate cancer is diagnosed in about 220,000 men each year in the United States and the disease kills about 35,000 men in the country annually, according to the National Cancer institute.