Our overarching goal is to identify modifiable risk factors for fatal prostate cancer. Prostate cancer remains the second leading cause of cancer-death in the United States (U.S.), but known demographic and genetic risk factors have limited value in delaying progression. Further investigation in U.S. populations is problematic because widespread and selective prostate-specific antigen (PSA) testing is so strongly associated with the stage at diagnosis that any association between a risk factor and PSA testing could easily overwhelm a modest by important etiologic association. To remove this known detection bias, we propose a prospective investigation to determine the association between obesity, tobacco, and alcohol use with fatal prostate cancer using data from the Asian Cohort Consortium (ACC). Asian nations rarely perform PSA tests, and most prostate cancer patients in Asia are diagnosed with advanced or metastatic disease. The ACC is a unique resource that has harmonized data across 15 prospective cohort studies and includes over 450,000 men with approximately 3.5 million person-years follow-up. Prostate cancer is far less common in Asia than the U.S., and a prospective study would only be possible with such a consortium. Using a nested case- control design, each of the 507 recorded prostate cancer deaths to date will be individually matched to 10 controls by age (1 year) and cohort. Multivariable conditional logistic regression will be used to investigate associations between BMI, tobacco, and alcohol use with fatal prostate cancer. This project provides an exceptional opportunity to provide the first systematic prospective investigation of modifiable factors for fatal prostate cancer, while minimizing detection bias from selective PSA testing and subsequent treatment. Our results may form the basis for recommendations to prevent prostate cancer mortality in Asia, and more generally, in populations that are not routinely PSA-tested. Furthermore, results may also form the basis for adjuvant care recommendations among men diagnosed with localized disease by at risk for progression to an advanced stage and for death. PUBLIC HEALTH RELEVANCE: Prostate cancer is a leading cause of cancer-related mortality, while widespread screening had led to the over-treatment of early stage and non-fatal disease. This prospective investigation of modifiable factors for fatal prostate cancers while reducing as much as possible any influence of selective prostate cancer screening and detection. Our results may suggest new prevention or adjuvant care strategies to reduce mortality and avoid comorbidities such as incontinence and impotency derived from unnecessary treatment.