Association of Plant Protein Intake With Risk of Incident CKD: A UK Biobank Study

Rationale & Objective: Data suggest that various dietary interventions slow kidney disease progression and improve clinical outcomes for those with chronic kidney disease (CKD). However, the association between plant protein intake and incident CKD has been uncertain. Study Design: Prospective cohort study. Setting & Participants: 117,809 participants who completed at least 1 dietary questionnaire and had an estimated glomerular filtration rate (eGFR) >= 60 mL/min/1.73 m(2), a urinary albumin-creatinine ratio (UACR) < 30 mg/g, and no history of CKD. Exposure: Daily plant protein intake in g/kg/day. Outcome: Incident CKD based on the International Classification of Diseases, 10th Revision (ICD-10) or the Office of Population Censuses and Surveys Classification of Interventions and Procedures, version 4 (OPCS-4) codes. Analytical Approach: A cause-specific proportional hazards analysis incorporating competing risks that treated death occurring before incident CKD as a competing event. Results: During a median follow-up period of 9.9 years, incident CKD occurred in 3,745 participants (3.2%; incidence rate, 3.2 per 1,000 person-years). In a multivariable model, the adjusted hazard ratio (AHR) for the second, third, and highest quartiles of plant protein intake was 0.90 (95% CI, 0.82-0.9 9), 0.83 (95% CI, 0.75-0.92), and 0.82 (95% CI, 0.730.93), respectively, compared with the lowest quartile. Modeled as a continuous variable, the AHR per 0.1 g/kg/day plant protein intake increase was 0.96 (95% CI, 0.93-0.9 9). This beneficial association was also consistent in secondary analyses for which CKD was defined based on codes or 2 consecutive measures of eGFR < 60 mL/min/1.73 m(2) or UACR > 30 mg/ g. Various sensitivity analyses demonstrated consistent findings. Limitations: Potential incomplete dietary assessments; limited generalizability due to the characteristics of participants in the UK Biobank Study. Conclusions: In this large, prospective cohort study, greater dietary plant protein intake was associated with a lower risk of incident CKD. Further interventional studies demonstrating the kidney-protective benefits of plant protein intake are warranted.