Platz stressed the strengths of this study, including that it was conducted prospectively and consisted of large numbers of men in most of the ethnic groups studied. An estimated 30 percent of prostate cancer cases occurred among Japanese men>

"There is no reason to think that the differences in results by ethnicity are explained by bias. Different racial and ethnic populations tend to have differing proportions of fat relative to lean mass and carry their fat mass differently. These differences may be used as a launching point for the next line of research: The nature of the weight gain ??” amount of fat gained and distribution of the fat gained in association with prostate cancer risk overall, and by stage and grade," added Platz, who is also an editorial board member for Cancer Epidemiology, Biomarkers & Prevention.

This study underscores the importance of investigating cancer etiology in diverse populations and researchers should conduct additional studies.

"These results do not warrant a change in the current public health messages about obesity: Men of normal weight in all racial/ethnic groups should be encouraged to avoid weight gain and men who are overweight and obese should be encouraged to lose weight for good health in general," Platz added.

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