Which of the following is an age-dependent change in renal function?

Decreased GFR (glomerular filtration rate) is an age-dependent change in renal function that occurs as individuals grow older. With aging, there is a natural decline in kidney function, which is often quantified by a decrease in GFR. This decline can be attributed to a variety of factors, including a reduction in the number of functioning nephrons, changes in renal blood flow, and alterations in glomerular structure and function.

The decrease in GFR can lead to a reduced ability of the kidneys to excrete waste products and maintain fluid and electrolyte balance, making older adults more susceptible to conditions such as kidney disease and related complications. It's important to recognize that this decrease in GFR is a normal aspect of aging, as opposed to a pathological change.

In contrast, other options such as increased GFR, increased creatinine clearance, and increased renal blood flow do not characterize typical age-related changes in renal function. Instead, these alterations are more common in younger adults and may even represent hyperfiltration states rather than decline associated with aging. Therefore, the recognition of decreased GFR is crucial in understanding how renal function naturally declines with age.