MedicalResearch.com Interview with: Ying Wang, PHD | Senior Epidemiologist American Cancer Society, Inc. 250 Williams St. Atlanta, GA 30303 MedicalResearch.com: What is the background for this study? Dr. Wang: Although evidence is still limited, previous studies suggest that vigorous activity and brisk walking after prostate cancer diagnosis might be associated with lower risk of prostate cancer progression and disease-specific mortality. We still don’t know if physical activity before diagnosis is associated with the risk or not. This is also important because reverse causation is a concern in the analysis of post-diagnosis physical activity, especially for vigorous activity, that men with advanced diseases may reduce their activity level. In contrast, pre-diagnosis physical activity is less subject to reverse causation and may represent a long-term behavior. When walking, the most common type of physical activity, was examined separately in previous studies, it was not evaluated in the absence of other activities. No study has examined sitting time in relation to mortality among prostate cancer survivors, although previous study suggests longer sitting time is associated with higher risk of all-cause mortality in healthy populations. So in our study, we aimed to examine physical activity, walking only, and sitting time both before and after diagnosis in relation to prostate cancer-specific mortality. (more…)