Previous studies have shown that in prostate cancer patients who are considered obese there is a higher risk of the disease recurring after surgery. Now researchers at Duke University Medical Center who took a second look at the information contained in a large database of prostate cancer patients have been able to make another conclusion: Black or white, being obese is just as bad for both.

Statistically black men are more likely than whites to develop, and indeed die from the disease and the incidence of obesity in black prostate cancer patients is higher than in white. This led some studies to suggest that obesity was more of a risk factor for the black patients than their white counterparts.

But according to a senior author on the paper, Stephen Freeland MD, who is an associate professor of urology and pathology at the Duke Prostate Center that is simply not the case. “Obesity leads to worse cancer in both groups.”

Freedland and his colleagues, including the senior author Jayakrishnan Jayachandran, M.D, a urologic oncology fellow at the same institute reexamined the data in the medical records of 1,415 men who had been enrolled in the Shared Equal Access Regional Cancer Hospital (aka SEARCH) program who had undergone a radical prostatectomy to treat prostate cancer. More than 47% of the sample was black men.

Researchers looked at the relationship between the body mass index of an individual and the aggressiveness of the cancer, which was determined by the risk of post surgery recurrence. Unlike other studies they found no relationship between a patient’s race and obesity.

Many of the men, regardless of race, whose records were included in the study were obese, almost a third.

“We found that higher BMI was associated with significantly increased risk of cancer recurrence for both blacks and whites,” writes Jayachandran “Though prior SEARCH-based studies from our group found that obesity was associated with a higher risk of disease progression as measured by a rising PSA after surgery, it now appears that being obese just means a poorer prognosis, period, regardless of race.”

Researchers on this study are not sure just why that is, speculating it may have some connection with altered hormone levels in obese patients. Jayachandram notes that obesity is often associated with more estrogen and less testosterone being present in the body. It may those lower levels of testosterone that promote more aggressive tumor growth as other studies have recently suggested.

The study was published in the journal Cancer and was funded by the Department of Veterans Affairs, the National Institutes of Health, The Georgia Cancer Coalition, the Department of Defense Prostate Cancer Research Program, and the American Urological Association Foundation/Astellas Rising Star in Urology Award.