The kidney and the elderly: why does the risk increase? 
Ageing is characterised by a decline in renal function and by a higher susceptibility to renal diseases.  This has been defined by Fliser as the "myth of the inexorable decline of renal function with senescence" and is a consequence of multiple factors that predispose to renal damage.  These include physiological factors that cannot be modified or treated, and pathological factors that can be treated and, sometimes, prevented; the former are represented by anatomic, molecular, and functional changes that physiologically occur during the ageing process; the latter-by acquired risk factors, whose incidence increases in the elderly, thus predisposing to or aggravating the renal damage.  These include increased prevalence of age-related diseases, increased consumption of potentially nephrotoxic drugs, increased necessity of radiological procedures using iodinated contrast media, and increased necessity of major surgery.  In this review we analyse these factors and their relevance in increasing the risk of renal damage in the elderly.