• Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
• Department of Clinical Nutrition, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China.
• Department of Clinical Nutrition, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China. Electronic address: tswcqmu@cqmu.edu.cn.
• Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China. Electronic address: penglinglong_cqmu@cqmu.edu.cn.
• Department of Gastrointestinal Surgery, Chongqing Jiulongpo People's Hospital, Chongqing, China; Department of General Surgery, Xipeng Town Health Center of Jiulongpo District, Chongqing, China. Electronic address: 932721020@qq.com.

OBJECTIVES: To explore the relationships between dietary potential acid load and renal cancer (RC) incidence and mortality.

STUDY DESIGN: A prospective cohort study involving 97,166 U S. adults aged 55-74 years.

METHODS: Data utilized in this study were drawn from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO). Dietary potential acid load was assessed by dietary acid load (DAL), potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores using a validated Diet History Questionnaire (DHQ). Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for RC incidence and mortality with adjustment for potential confounders. Restricted cubic spline (RCS) plots were utilized to reveal whether there were nonlinear associations between the DAL, PRAL, and NEAP scores and RC incidence and mortality.

RESULTS: During a follow-up period of 859,907 and 1,467,573 person-years, 423 RC cases and 221 mortality cases were documented. DAL, PRAL, and NEAP scores were positively associated with RC incidence (DAL: HR 1.41; 95% CI 1.05, 1.90; P-trend = 0.010; PRAL: HR 1.45; 95% CI 1.10, 1.91; P-trend = 0.010; NEAP: HR 1.39; 95% CI 1.04, 1.85; P-trend = 0.029). Similar associations were observed between DAL, PRAL, and NEAP scores and RC mortality. The RCS plots demonstrated a nonlinear association between DAL score and RC risk, while a linear association was observed between DAL score and RC mortality. Similar linear associations were found between PRAL and NEAP scores and RC incidence and mortality.

CONCLUSION: A higher dietary potential acid load was associated with higher risk of RC incidence and mortality in American adults.