• Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
• Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
• Department of Nephrology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
• Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
• Department of Endocrine and Breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
• Department of Geriatrics, The Fifth People's Hospital of Chengdu, Chengdu, China.
• Department of Nutrition and Food Hygiene, School of Public Health and Management, Chongqing Medical University, Chongqing, China.
• Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China. gczhong1991@stu.cqmu.edu.cn.

BACKGROUND: Modern Western diets are rich in acidogenic foods. Human and in vitro studies suggest a potential link between dietary acid load and cancer risk. However, no epidemiologic studies have investigated the association of dietary acid load with the risk of pancreatic cancer. Therefore, we conducted a prospective cohort study to fill this gap.

METHODS: A population-based cohort of 95,708 American adults was identified. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) were used to assess dietary acid load of each subject, with greater values indicating greater dietary acid load. Cox regression was used to estimate risk estimates for pancreatic cancer incidence. Predefined subgroup analysis was used to identify the potential effect modifiers.

RESULTS: A total of 337 pancreatic cancer cases were observed during 848,534.0 person-years of follow-up. PRAL score was found to be positively associated with the risk of pancreatic cancer [fully adjusted HR_{quartile 4 vs. 1}: 1.73; 95% confidence interval (95% CI), 1.21-2.48; P _trend = 0.001] in a nonlinear dose-response pattern (P _nonlinearity = 0.012). Subgroup analysis found that the positive association of PRAL score with the risk of pancreatic cancer was more pronounced in subjects aged <65 years than in those ≥65 years (P _interaction = 0.018). Similar results were obtained for NEAP score.

CONCLUSIONS: Higher dietary acid load is associated with a higher risk of pancreatic cancer. Future studies should validate our findings in other populations and settings.

IMPACTS: This is the first epidemiologic study suggesting that reducing dietary acid load may be useful in primary prevention of pancreatic cancer.