VDR and polycystic kidney disease: Variables that yielded significance in univariate analyses of survival (age at the beginning of the study, diabetic nephropathy, polycystic kidney disease and chronic glomerulonephritis as causes of ESRD, CAD, the ability to develop antibodies to HBV surface antigen in response to HBV vaccination or infection, and serum PTH concentration) as well as RRT vintage prior to the study onset were used in multivariate analyses together with each polymorphic variant being also solely shown as involved in survival (GC rs2298849 and VDR rs2228570).