Racial Disparities in Prostate Cancer Mortality Rates Partially Explained By Differences in Dietary and Lifestyle Factors

Introduction: Black individuals have 2.1 times higher prostate cancer mortality rates than White individuals in the United States. Several dietary and lifestyle factors may influence the risk of lethal prostate cancer. This study evaluated to what extent differences in the prevalence of these modifiable risk factors by race could explain racial disparities in prostate cancer mortality. Methods: We compared the prevalence of seven potentially modifiable risk factors for lethal prostate cancer among Black and White individuals, using the National Health and Nutrition Examination Study at two time points (1988–1994; 2017–2018). Relative risks for lethal prostate cancer were estimated in the Health Professionals Follow-up Study. We calculated the population attributable fraction (PAF) for each factor by self-identified race, defined as the reduction in mortality that would be achieved if the population had been entirely unexposed, compared with the current exposure pattern. We also calculated the difference in the PAF between Black and White individuals, assuming causality of risk factors and no multiplicative effect measure modification by race. Results: Based on data from NHANES III (1988–1994), the largest prevalence differences between Black and White individuals were for vitamin D deficiency, current smoking, and coffee, respectively. Elimination of these risk factors among Black individuals could have led to a larger reduction in lethal prostate cancer in comparison to eliminating these same risk factors among White individuals. Given the prevalence of these risk factors in 2017–2018, current interventions on vitamin D deficiency, current smoking, and coffee could influence future PAF differences for lethal prostate cancer mortality among Black individuals compared to White individuals. Conclusions: Differences in the prevalence of some modifiable lifestyle and dietary factors are potentially responsible for a portion of the racial disparity in prostate cancer mortality.