• Department of Urology, Beijing Chaoyang Hospital Affiliated to Capital Medical University, Beijing, China.

This study aimed to evaluate the relationship between the consumption of different dietary fatty acids and the risk of bladder cancer. A quantitative analysis was conducted using data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, which included 101,731 participants. The Cox proportional hazards model was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for bladder cancer risk in relation to dietary fatty acid intake. During a median follow-up of 11.3 years, 861 bladder cancer cases were identified. After fully adjusting for potential confounders in a multivariate Cox regression model, no significant association was found between dietary fatty acid consumption and bladder cancer risk. Subgroup analysis revealed significant interactions with gender (p < 0.001) and smoking status (p < 0.001). Gender-specific analysis showed that a higher intake of monounsaturated fatty acids (MUFAs) was linked to a reduced risk of bladder cancer in females (HR: 0.62; 95% CI: 0.39-0.99, P-trend = 0.028). However, restricted cubic spline analysis revealed no linear relationship between MUFA intake and bladder cancer risk in the overall group or gender-specific subgroups. The association between dietary fatty acids and bladder cancer risk is influenced by factors like gender and smoking status. In females, moderate MUFA intake may reduce bladder cancer risk, but higher intake does not provide additional benefits.