Dietary patterns after prostate cancer diagnosis in relation to disease-specific and total mortality

Abstract

Men diagnosed with nonmetastatic prostate cancer have a long life expectancy, and many die of unrelated causes. It is therefore important to know to what extent post-diagnostic diet may affect disease-specific and overall mortality. A total of 926 men participating in the Physicians' Health Study diagnosed with nonmetastatic prostate cancer completed diet questionnaires for a median of 5.1 years after diagnosis, and were followed thereafter to assess mortality for a median of 9.9 years since questionnaire completion. Two post-diagnostic dietary patterns were identified: a Prudent pattern, characterized by higher intake of vegetables, fruits, fish, legumes, and whole grains; and a Western pattern, characterized by higher intake of processed and red meats, high-fat dairy and refined grains. Cox regression was used to estimate multivariable-adjusted hazard ratios (HR) and 95% confidence intervals (CI). During 8,093 person-years of follow-up, 333 men died, 56 (17%) of prostate cancer. The Western pattern was significantly related to a higher risk of prostate cancer-specific and all-cause mortality. Comparing men in the highest versus the lowest quartile of the Western pattern, the HRs were 2.53 (95% CI, 1.00-6.42; P-trend = 0.02) for prostate cancer-specific mortality and 1.67 (95% CI, 1.16-2.42; P-trend = 0.01) for all-cause mortality. The Prudent pattern was associated with a significantly lower all-cause mortality (HRQuartile 4 vs. Quartile 1: 0.64; 95% CI, 0.44-0.93; P-trend = 0.02); the relationship with prostate cancer-specific mortality was inverse but not statistically significant. A post-diagnostic Western dietary pattern was associated with higher prostate cancer-specific and all-cause mortality, whereas a Prudent dietary pattern was related to lower all-cause mortality after prostate cancer diagnosis.