Association between kidney function and the risk of cancer: Results from the China Health and Retirement longitudinal study (CHARLS)

Objective: Increased cancer risk after dialysis or transplantation has been recognized, but studies of cancer in pre-dialysis chronic kidney disease (CKD) are extremely limited. Therefore, we aim to investigate the risk of cancer in individuals with reduced kidney function. Methods: This study was based on China Health and Retirement Longitudinal Study (CHARLS), a nationally representative population aged >= 45 years old. We included 11 508 (5364 male) individuals with measurement of serum creatinine and without history of cancer at baseline. Incident cancer cases were documented in the biennial questionnaire. Results: The mean age was 58.7 +/- 9.8 years. Participants with estimated glomerular filtration rate (eGFR) >= 90 ml/min/1.73m(2), 60 to 89 ml/min/1.73m(2), and eGFR < 60 ml/min/1.73m(2 )accounted for 62.9%, 33.7% and 3.4%, respectively. During 42 895 person-years' follow-up, 217 new cases of cancer were recorded. In participants with eGFR < 90 ml/min/1.73m(2), cubic spline showed linear relationship between the risk of cancer and eGFR, while remained stable and no association in participants with eGFR > 90 ml/min/1.73m(2). Compared to participants with eGFR >= 90 ml/min/1.73m(2), those with eGFR < 60 ml/min/1.73m(2) was associated with the increased risk of cancer in the fully adjusted model (hazard ratio 2.08; 95% confidence interval 1.22-3.53); and the risk for kidney and lung cancers was higher among those with eGFR < 60 ml/min/1.73m(2). Conclusion: Reduced kidney function is associated with a higher risk of cancer and should be integrated into risk-stratification of cancer screening and management.