Dietary Acid Load and Bladder Cancer Risk: An Epidemiologic Case-Control Study

Introduction: Dietary acid load contributes to metabolic acidosis, closely linked to cancer development through inflammation and cell transformation. There is very limited epidemiologic evidence; linking diet-dependent acid load and cancer risk. Since there are few published studies specifically on urinary pH and bladder cancer (BC) risk, we sought to explore this association in the present study. Methods: A case-control study was performed in 765 patients (255 cases and 510 age- matched controls) through a multi-topic inquiry including a food frequency questionnaire. Food-derived nutrients were calculated from available databases. The dietary acid load was calculated based on two validated measures including potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores. Odds ratios (OR) and their 95% confidence intervals were estimated by unconditional logistic regression adjusted for potential confounders. Results: We found direct associations between dietary acid load and BC risk. Both acid load scores were significantly associated with an increased BC risk (OR=1.74 and OR=1.83 for PRAL and NEAP scores, respectively). Linear trends were found for both risk estimates. Conclusions: A high dietary acid load may contribute to BC development. Both acid load scores were directly associated with animal-based foods (mainly meat) and inversely associated with the intake of plant-based foods. To our knowledge, this is the first epidemiologic case-control study analyzing associations of dietary acid load and BC risk in the Latin American population. Further research is warranted to confirm our findings.