Fat quality, not quantity, linked to reduced risk of advanced and lethal prostate cancer in US populations: a large prospective multicenter study.

[BACKGROUND] Epidemiological evidence on dietary fat intake and advanced prostate cancer (PCa) risk is limited and inconclusive; moreover, no prospective study has been conducted to investigate the association between fat quality and quantity and advanced and lethal PCa risk.

[METHODS] This prospective cohort included 49 424 men from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. The fat quality index (FQI) and low-fat diet score (LFDs) were used to evaluate the quality and quantity separately, where higher scores indicated greater adherence. Cox proportional hazards regression was used to evaluate the risk of PCa incidence and mortality. Subgroup analyses were conducted to identify potential confounders. Sensitivity analyses were performed to assess the robustness of the results.

[RESULTS] During follow-up, a total of 857 incident cases of advanced PCa, including 425 lethal PCa were documented. Individuals in the highest compared with the lowest quartiles of FQI had a lower advanced PCa [hazard ratioQ4 versus Q1 : 0.72, 95% confidence interval (CI): 0.58-0.88, P for trend = 0.002] and lethal PCa (hazard ratioQ4 versus Q1 : 0.65, 95% CI: 0.48-0.87, P for trend = 0.005). This inverse association between FQI and advanced PCa risk was not observed for nonlethal PCa. Subgroup analyses indicated this inverse association of FQI with advanced PCa was only observed in participants with higher LFDs. No significant associations were found between LFDs and the risk of advanced and lethal PCa.

[CONCLUSION] Our findings suggest focusing on higher quality, rather than restricting the quantity of fat intake, may be an effective approach to reduce the risk of advanced PCa in the US population, particularly for lethal PCa.