Friday, April 17, 2015
African-American men in general are at higher risk of prostate cancer, including being at a higher risk of death from the disease - but why this is has not been clearly defined
An analysis now suggests a relationship with obesity. Higher BMI in the study was associated with prostate cancer in all men, but African-Americans were at greater danger; the chances of these men getting prostate cancer increased fourfold for obesity compared with normal weight. The relationship between obesity and prostate cancer is complex - but the risk is clearly higher in African-Americans, the study finds. The analysis covers 3,398 African-American and 22,673 non-Hispanic white men who had taken part in the SELECT trial. They formed a prospective study cohort who had originally been recruited to test whether selenium and vitamin E had a preventive role against prostate cancer - but they gave obesity-related data in the process. Any men who had not yielded data on body mass index (BMI) and other relevant variables were left out of this analysis. Prostate cancer incidence was the outcome tracked and has been analyzed for its relationship to obesity and race by Wendy Barrington, PhD, of the Fred Hutchinson Cancer Research Center in Seattle, WA. Dr. Barrington - assistant professor in psychosocial and community health at the University of Washington School of Nursing - accessed data on total numbers of prostate cancer diagnoses, and which of these were low-grade or high-grade. Grading had been performed in the pathology lab on biopsy samples - to reach a Gleason score, which below 7 means low-grade prostate cancer, or high-grade at 7 and greater. Key among her findings was that the risk of developing prostate cancer in the African-American men who were obese approached four times the risk of African-American men who had normal weight. Using BMI, the analysis found a 28% risk of getting prostate cancer for the African-American men who had a BMI below 25 and a 103% risk for those with a BMI of 35 or more, representing obesity. By contrast, "obesity was not associated with risk of total prostate cancer" among the non-Hispanic white men in the study, the authors conclude. Dr. Barrington confirmed the main message of the findings. As corresponding and primary author, she said: "The main take-home point for practicing physicians is to recognize that obesity has a different relationship to prostate cancer risk in African-American compared to non-Hispanic white men."