IntroductionBy applying on two-sample Mendelian randomization and systematic review and meta-analysis we investigated the association between caffeine and coffee intake with prevalent CKD and markers of renal function.Material and methodsFor the individual data analysis we analysed the NHANES data on renal function markers and caffeine intake. MR was implemented by using summary-level data from the largest ever GWAS conducted on coffee intake (N=91,462) and kidney function.ResultsFinally, we included the data of 18,436 participants, 6.9% had prevalent CKD (based on eGFR). Caffeine intake for general population was 131.1±1.1 mg. The percentage of participants with CKD, by caffeine quartile was 16.6% in the first (lowest) quartile, 13.9% in the second, 12.2% in the third and 11.0% in the top quartile (p<0.001). After adjustment, for increasing quartiles for caffeine consumption, mean urine albumin, albumin-creatinine ratio and estimated glomerular filtration rate (GFR) did not change significantly (p>0.234). In fully adjusted logistic regression models, there was no significant difference in chances of CKD prevalence (p-trend=0.745). In the same line, results of MR showed no impact of coffee intake on CKD (IVW=β: -0.0191, SE: 0.069, p=0.781), on eGFR (overall= IVW= β: -0.0005, SE: 0.005, p=0.926) both in diabetic (IVW= β: -0.006, SE: 0.009, p=0.478), and non-diabetic patients (IVW= β: -6.772, SE: 0.006, p=0.991). Results from the meta-analysis indicted that coffee consumption was not significantly associated with CKD (OR: 0.85, 95%CI 0.71-1.02, p=0.090, n=6 studies, I2=0.32).ConclusionsBy implementing on different strategies, we have highlighted no significant association between coffee consumption with renal function and chance of CKD.