Prostate cancer risk patterns vary by ethnicity
A team of scientists led by researcher Brenda Hernandez, Ph.D., M.P.H.-an assistant professor at the University of Hawai'i at Mānoa's Cancer Research Center of Hawai'i-has reported that body mass in younger and older adulthood, and weight gain between these life periods, may influence a man's risk for prostate cancer. This risk varies among different ethnic groups, according to findings reported in a study published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
Dr. Hernandez and colleagues studied the relationship in a multiethnic population consisting of blacks, Japanese, Hispanics, Native Hawaiians and whites, and compared differences among age groups using the Multiethnic Cohort, a longitudinal study of men 45-75 years of age established in Hawai'i and California from 1993-1996. Of the 83,879 men who participated in the study, 5,554 developed prostate cancer. Overall, men who were overweight or obese by age 21 had a decreased risk of localized and low-grade prostate cancer, according to Dr. Hernandez.
Their results suggested that being overweight in older adulthood was associated with increased prostate cancer risk among white and Native Hawaiian men, but a decreased risk among Japanese men. While excessive weight gain between younger and older adulthood was observed to increase the risk of advanced and high-grade prostate cancers in white men and increase the risk of localized and low-grade disease in black men, it appeared to decrease the risk of localized prostate cancer in Japanese men.
Dr. Hernandez said, "The relationship of certain characteristics, such as body size, with cancer risk may vary across ethnic groups due to the combined influence of both genes and lifestyle."
Obesity is a known risk factor in other common cancers, including colorectal cancer and breast cancer in post-menopausal women. However, the relationship between body size and prostate cancer risk is not entirely understood.
Excess fat is associated with a number of conditions that contribute to cancer development including low-grade chronic inflammation, insulin resistance, metabolic abnormalities, and hormone imbalances. These conditions may in turn contribute to more aggressive prostate malignancies.