Empirically derived dietary patterns and prostate cancer risk: a systematic review and meta-analysis of prospective cohorts.

Prostate cancer (PCa) is the second most common cancer in men and the fourth worldwide. Diet has been suspected as a contributor to PCa onset and progression; however, evidence remains inconsistent, because many studies focus on individual foods and use heterogeneous methods to derive dietary patterns. This systematic review evaluates the association between empirically derived dietary patterns and overall PCa risk in prospective cohort studies. A literature search was conducted on PubMed, Web of Science, Embase, the Cochrane Library, and Food Science and Technology Abstracts, following preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Risk estimates comparing the highest versus lowest adherence categories were extracted. A random-effects meta-analysis using restricted maximum likelihood estimation pooled hazard ratios for overall PCa risk. Six eligible cohort studies were included. Two main dietary patterns were identified: a 'western' pattern, characterized by high intakes of red and processed meats, sweets, desserts, and a 'prudent' pattern characterized by high intakes of fruits, vegetables, fish, and seafood. No significant association with overall PCa was observed: prudent, hazard ratio Pooled  = 0.98; confidence interval 95% [0.91-1.06]; western, hazard ratio Pooled  = 1.07; confidence interval 95% [0.93-1.22]. Empirically derived dietary patterns were not significantly associated with overall PCa risk. Some evidence suggested an association between western dietary pattern and localized and aggressive PCa in populations with limited prior exposure, highlighting the role of dietary shifts. However, these findings were based on a limited number of studies, reflecting the scarcity of prospective cohort data. Future research should aim to standardize dietary pattern derivation and confounder selection to improve comparability across studies.