Obesity may raise prostate cancer risk

A new study shows that body mass in younger and older adulthood and weight gain during these periods may influence a man's risk of prostate cancer although the effect varies among different ethnic groups.

The study was conducted by Brenda Hernandez, Ph.D., M.P.H.at the University of Hawaii and published in the Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

For the study, Hernandez and colleagues analyzed data from 83,879 men of whom 5,554 developed prostate cancer and found that overall men who were overweight or obese by age 21 were at low risk of localized and low-grade prostate cancer.

Considering men in individual ethnic groups, the researchers found being overweight in older adulthood were linked to increased risk of prostate cancer among white and Native Hawaiian men. The opposite association was observed among Japanese men.

Being overweight or obese between younger and older adulthood was associated with increased risk of advanced and high grade prostate cancers in whites and was linked to elevated risk of localized prostate cancer in Japanese men.

Specifically, overweight and obesity between younger and older adulthood was associated with increased risk of advanced and high grade prostate cancers in white men and localized and low-grade cancer in black men. But excessive weight gain apparently decreased the risk of localized prostate cancer among Japanese men.

Obesity has been recognized as a risk factor for other common cancers such as colorectal cancer and breast cancer in post-menopausal women. But the relationship between body weight and prostate cancer risk had not been clear until this study was completed.

Excess fat is linked to certain conditions that boost cancer development including low-grade inflammation, insulin resistance, metabolic abnormalities, and hormone imbalances, according to the press release by the University of Hawaii.

Results suggest that Asian men may afford to gain more pounds of fat without increasing their risk for prostate cancer. Asian men tend to accumulate more fat in their upper bodies and less fat in their lower bodies compared to men in other ethnic groups. It seems that the distribution of excess fat makes a difference in cancer risk.

By David Liu davidl at foodconsumer dot org