Fat intake after diagnosis and risk of lethal prostate cancer and all-cause mortality.

IMPORTANCE Nearly 2.5 million men currently live with prostate cancer in the United States, yet little is known about the association between diet after diagnosis and prostate cancer progression and overall mortality. OBJECTIVE To examine postdiagnostic fat intake in relation to lethal prostate cancer and all-cause mortality. DESIGN, SETTING, AND PARTICIPANTS Prospective study of 4577 men with nonmetastatic prostate cancer in the Health Professionals Follow-up Study (1986-2010). EXPOSURES Postdiagnostic intake of saturated, monounsaturated, polyunsaturated, trans, animal, and vegetable fat. MAIN OUTCOMES AND MEASURES Lethal prostate cancer (distant metastases or prostate cancer-specific death) and all-cause mortality. RESULTS We observed 315 events of lethal prostate cancer and 1064 deaths (median follow-up, 8.4 years). Crude rates per 1000 person-years for lethal prostate cancer were as follows (highest vs lowest quintile of fat intake): 7.6 vs 7.3 for saturated, 6.4 vs 7.2 for monounsaturated, 5.8 vs 8.2 for polyunsaturated, 8.7 vs 6.1 for trans, 8.3 vs 5.7 for animal, and 4.7 vs 8.7 for vegetable fat. For all-cause mortality, the rates were 28.4 vs 21.4 for saturated, 20.0 vs 23.7 for monounsaturated, 17.1 vs 29.4 for polyunsaturated, 32.4 vs 17.1 for trans, 32.0 vs 17.2 for animal, and 15.4 vs 32.7 for vegetable fat. Replacing 10% of energy intake from carbohydrate with vegetable fat was associated with a lower risk of lethal prostate cancer (hazard ratio [HR], 0.71; 95% CI, 0.51-0.98; P = .04) and all-cause mortality (HR, 0.74; 95% CI, 0.61-0.88; P = .001). No other fats were associated with lethal prostate cancer. Saturated and trans fats after diagnosis (replacing 5% and 1% of energy from carbohydrate, respectively) were associated with higher all-cause mortality (HR, 1.30 [95% CI, 1.05-1.60; P = .02] and 1.25 [95% CI, 1.05-1.49; P = .01], respectively). CONCLUSIONS AND RELEVANCE Among men with nonmetastatic prostate cancer, replacing carbohydrates and animal fat with vegetable fat may reduce the risk of all-cause mortality. The potential benefit of vegetable fat for prostate cancer-specific outcomes merits further research.