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).