Race and Ethnicity, Lifestyle, Diet, and Survival in Patients With Prostate Cancer.

IMPORTANCE

Prostate cancer (PCa) remains a leading cause of cancer-related death among men in the US.

OBJECTIVE

To evaluate the association of healthy lifestyle and dietary behaviors with survival after a nonmetastatic PCa diagnosis in a multiethnic population.

DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study was conducted among men aged 45 to 75 years enrolled between 1993 and 1996 in the Multiethnic Cohort study. Participants with nonmetastatic PCa completed a questionnaire after diagnosis (2003-2008) and were followed up until death or loss to follow-up. Data were analyzed from January 10, 2023, to May 20, 2024.

EXPOSURES

Lifestyle and dietary patterns were assessed after diagnosis using 3 PCa behavior scores and 13 dietary indices (4 prioritized scores: the Healthy Eating Index-2015, Healthful Plant-Based Diet Index, Dietary Inflammatory Index, and Empirical Dietary Index for Hyperinsulinemia).

MAIN OUTCOMES AND MEASURES

Cox proportional hazards models were used to evaluate multivariable-adjusted associations of each PCa behavior score with all-cause, cardiovascular disease (CVD), and PCa-specific mortality.

RESULTS

A total of 2603 men with nonmetastatic PCa (mean [SD] age, 69.6 [7.1] years) were followed up, and 1346 deaths were documented, including 356 (24.6%) from CVD and 197 (14.6%) from PCa. The median (IQR) follow-up was 10.9 (IQR, 6.8-12.7) years from questionnaire return and 14.5 (IQR, 11.8-18.0) years from diagnosis. The 2021 PCa Behavior Score was associated with reduced risks of all-cause (hazard ratio [HR] per point, 0.69; 95% CI, 0.63-0.77) and CVD-related (HR, 0.67; 95% CI, 0.56-0.79) mortality. This score was also associated with a lower risk of PCa-specific mortality among African American men (HR, 0.46; 95% CI, 0.24-0.88) but not in the other racial and ethnic groups. Comparing quintile 5 (highest score) with 1 (lowest score), the Empirical Dietary Index for Hyperinsulinemia was positively associated with all-cause (HR, 1.37; 95% CI, 1.02-1.84) and CVD-related (HR, 1.96; 95% CI, 1.15-3.33) mortality, whereas the Healthful Plant-Based Diet Index was associated with a reduced risk of all-cause (HR, 0.75; 95% CI, 0.58-0.97); findings for CVD-related mortality were not statistically significant (HR, 0.67; 95% CI, 0.44-1.03). No associations were found between lifestyle or dietary patterns and PCa mortality.

CONCLUSIONS AND RELEVANCE

In this multiethnic cohort of patients with nonmetastatic PCa, healthier lifestyles were associated with improved overall survival but not with PCa-specific survival. Given the predominance of non-PCa-specific deaths, these findings support the need for health behavior counseling to treat comorbidities in men with PCa.