The kidneys undergo a multitude of structural and functional changes with advancing age. Structurally, there is a progressive loss of predominantly cortical renal mass, a decrease in the number of glomeruli, an increase in the proportion of sclerotic glomeruli, atherosclerotic vascular changes and interstitial changes resulting in atrophy and fibrosis. Functionally, there is a decline in the glomerular filtration rate (GFR), resulting primarily from a decrease in the number of functioning nephrons.