eGFR and Age: How Much Does It Fall After 40 and When Is It a Problem?

Kidney filtration naturally declines with age, but the rate varies widely, and the line between kidney aging and disease is contested. We explain how much eGFR falls on average after 40, what happens to nephrons, why equations change your result with age, what the dispute over age-based CKD thresholds is about and what can actually slow the decline.

Redakcja VitMode — Hormony i endokrynologiathe VitMode editorial team, no individual bylinesPublishedOctober 22, 202613 min readAbout 13 min left

How this article was made

Author: Redakcja VitMode — Hormony i endokrynologia — the VitMode editorial team, no individual bylines
Method: Prepared from primary sources: clinical trials, meta-analyses and guidelines. We describe study findings separately from our interpretation.
Source verification: Cited PubMed papers are automatically checked for a matching identifier, title and publication year.
Medical review: none — this article has not been reviewed by a physician
Last updated: October 22, 2026

The content is educational and does not replace medical advice. Read the full editorial process

Table of contents

TL;DR — key takeaways

→How much does eGFR fall with age, and is it normal after 40?
→What happens to the kidney with age: loss of nephrons
→How fast GFR falls: what the studies show
→Why the eGFR on your printout depends on age and does not always tell the whole truth
→The dispute: one threshold of 60 for everyone, or age-dependent thresholds?
→When a fall in eGFR is a problem: warning signs
→What can slow the decline? Levels of evidence
→Myths and facts about eGFR decline with age
→Limitations and summary
→Our editorial recommendation

How much does eGFR fall with age, and is it normal after 40?

Many readers get an eGFR in their forties lower than at thirty and ask: is this already kidney disease, or just ageing? The answer is inconvenient for simple schemes: both can be true at once. Nephrons are lost with age in everyone, but the pace depends on blood pressure, glucose, body weight, smoking and genes, and the boundary between normal ageing and disease is the subject of a lively dispute in nephrology.

In this article we discuss how much GFR really declines with age according to different studies, what happens to the kidney at the tissue level, how eGFR equations treat age, what follows from the dispute over age-based thresholds for chronic kidney disease and what (with what level of evidence) might slow the process. The creatinine and cystatin C results themselves are covered in our article on cystatin C, and early kidney damage in urine in our article on the ACR.

What happens to the kidney with age: loss of nephrons

Each kidney contains from several hundred thousand to over a million nephrons, the filtering units. Nephrons are not added after birth, and with age some of them become sclerosed and atrophy. Information on how large this loss is in healthy people comes from studies of kidney donors, who undergo CT imaging and biopsy before donation.

What does the research say?

The Substantial Loss of Nephrons in Healthy Human Kidneys with Aging

Denic A, Lieske JC, Chakkera HA et al. · J Am Soc Nephrol · 2017

Study findings

A study of 1,638 living kidney donors (Mayo Clinic and Cleveland Clinic): cortical volume from pre-donation CT and glomerular density from biopsy. Donors aged 18-29 had on average 990,661 non-sclerotic glomeruli per kidney and those aged 70-75 had 520,410, i.e. 48% fewer; cortical volume decreased by only 16%, and the proportion of globally sclerotic glomeruli on biopsy rose by only 15%. Fewer non-sclerotic glomeruli were independently associated with older age, shorter height, family history of end-stage renal disease, higher uric acid and lower measured GFR. The authors interpret the findings as atrophy and reabsorption of sclerotic glomeruli and hypertrophy of the remaining nephrons.

Moderate evidenceView the study on PubMed

This describes what the study found. Editorial interpretation follows in the text below.

What does the research say?

The association between age and nephrosclerosis on renal biopsy among healthy adults

Rule AD, Amer H, Cornell LD et al. · Ann Intern Med · 2010

Study findings

A cross-sectional study of 1,203 adult living kidney donors with a cortical biopsy taken at transplantation. The prevalence of nephrosclerosis (at least 2 chronic histological abnormalities) was 2.7% at ages 18-29, 16% at 30-39, 28% at 40-49, 44% at 50-59, 58% at 60-69 and 73% at 70-77. Adjustment for kidney function and chronic kidney disease risk factors did not explain the association with age. Limitation: donors are selected for health, so the picture does not cover the full spectrum of changes in the general population.

Moderate evidenceView the study on PubMed

This describes what the study found. Editorial interpretation follows in the text below.

Conclusion: structural changes in the kidney accumulate with age even in people judged healthy, and begin early: the share with nephrosclerosis already rises between ages 30 and 50. The remaining nephrons partly compensate for the loss by hypertrophy, which is why GFR falls more slowly than the glomerular count alone would suggest.

How fast GFR falls: what the studies show

The rate of decline depends on the population, the measurement method (measured GFR or eGFR) and on who was considered healthy. Three studies from different eras and countries show the range.

Study	Population and method	Result
Rowe et al. 1976 (Baltimore)	548 healthy men, 24-hour creatinine clearance	Cross-sectionally a fall from 140 to 97 ml/min/1.73 m² between ages 30 and 80 (about 0.9 ml/min a year by our own calculation); longitudinal data showed acceleration of decline with age
Imai et al. 2008 (Japan)	120,727 people aged 40+, creatinine eGFR (MDRD), 10-year follow-up	On average 0.36 ml/min/1.73 m² a year; more than twice as fast with proteinuria; faster with hypertension
Fehrman-Ekholm and Skeppholm 2004 (Sweden)	52 'healthy' people aged 70-110, iohexol clearance	A fall of about 1.05 ml/min a year; only 30% had a GFR above 70 ml/min/1.73 m²

Rate of decline in glomerular filtration in selected studies

What does the research say?

Slower decline of glomerular filtration rate in the Japanese general population: a longitudinal 10-year follow-up study

Imai E, Horio M, Yamagata K et al. · Hypertens Res · 2008

Study findings

An analysis of 120,727 people aged at least 40 taking part in annual health examinations in two 10-year periods (1988-1993 and 1998-2003); eGFR was calculated with the MDRD equation with a Japanese coefficient. The mean rate of GFR decline was 0.36 ml/min/1.73 m² per year. In men aged 50-79 the rate of decline was significantly higher with hypertension than without, and in people with proteinuria it was more than twice as high as without. Faster decline was also associated with low baseline GFR. The authors conclude that in the Japanese general population the decline in kidney function progresses slowly, and that hypertension, proteinuria and lower GFR are significant risk factors for faster decline.

Moderate evidenceView the study on PubMed

This describes what the study found. Editorial interpretation follows in the text below.

This shows two important things. First, the spread is large: from a fraction to about one millilitre per minute a year, depending on the population. Second, the average hides subpopulations: people with hypertension or proteinuria lose filtration significantly faster. So single 'age norms' should be treated as indicative rather than as a boundary between health and disease. Note also that the studies rely on different measurement methods and equations from those used today.

Why the eGFR on your printout depends on age and does not always tell the whole truth

Current eGFR equations (CKD-EPI 2021) use creatinine, age and sex. This means that at the same creatinine concentration an older person has a lower calculated eGFR than a younger one: the equation 'assumes' age-related decline in filtration. That is statistically sensible, but it has hidden consequences: in someone whose creatinine rises very slowly or not at all, eGFR will still slowly fall simply because age in the equation changes.

On the other hand, muscle mass also declines with age, which lowers creatinine production. As a result, a stable or even lower creatinine in an older person need not mean the kidneys work well: an equation based on creatinine alone can overstate filtration in people with sarcopenia. In such situations cystatin C or the combined eGFRcr-cys equation can help, as we describe in a separate article. In practice it is worth looking not at a single number but at the trend across successive tests, done by the same method in the same laboratory.

It is also important that measured GFR (for example iohexol clearance) is the standard and eGFR only an estimate of it. In a study of very old people the Cockcroft-Gault equation underestimated clearance (on average 46.2 versus a measured 67.7 ml/min/1.73 m²), showing that the choice of equation in older people has real consequences. Equations are not interchangeable, and so comparisons with results from other years can mislead if the method was changed.

The dispute: one threshold of 60 for everyone, or age-dependent thresholds?

Chronic kidney disease is currently diagnosed when eGFR stays below 60 ml/min/1.73 m² for at least three months or when there are other signs of kidney damage (for example albuminuria), regardless of age. Some nephrologists think this is a mistake.

What does the research say?

CKD: A Call for an Age-Adapted Definition

Delanaye P, Jager KJ, Bökenkamp A et al. · J Am Soc Nephrol · 2019

Study findings

An expert position paper calling for an age-dependent definition of chronic kidney disease. The authors point out that the 60 ml/min/1.73 m² threshold does not separate kidney disease from kidney aging, and that, in an extensive review of the literature, they found GFR declines with healthy aging without any overt signs of compensation (such as elevated single-nephron GFR) or kidney damage. Older living kidney donors, carefully selected for good health, have a lower predonation GFR than younger donors. From the CKD Prognosis Consortium meta-analyses, the GFR threshold above which the risk of mortality is increased is not the same at all ages: among younger persons mortality is increased at GFR below 75, and in elderly people only below 45 ml/min/1.73 m². The authors propose age-specific thresholds, which would reduce overdiagnosis of CKD in healthy older people and allow earlier identification in younger ones.

Moderate evidenceView the study on PubMed

This describes what the study found. Editorial interpretation follows in the text below.

What does the research say?

Age-adapted versus age-independent eGFR thresholds to diagnose CKD: integrating the debate and charting a balanced path forward

Delanaye P, Vart P, Floege J, Zoccali C · Clin Kidney J · 2025

Study findings

A review of positions in the debate. Proponents of age-adapted thresholds stress that many healthy older adults have an eGFR below 60, and that a fixed threshold risks overdiagnosis, anxiety and unnecessary treatment, and underrecognition of risk in younger people whose GFR is abnormal for their age. Proponents of age-independent thresholds point out that in older people with an eGFR of 45-59 the risk of kidney failure, cardiovascular events and death is raised even without albuminuria, that changing the definition could exclude high-risk people from beneficial therapies, and that 'healthy' reference populations may harbour undiagnosed disease. The authors suggest a balanced approach: individual risk assessment and shared decision-making instead of rigid thresholds.

Moderate evidenceView the study on PubMed

This describes what the study found. Editorial interpretation follows in the text below.

For the reader a simple practical conclusion follows: an 'eGFR of 55' in a 78-year-old with no proteinuria, well-controlled blood pressure and a stable trend is not the same as an 'endangered kidney', but neither is it a result to ignore. The assessment should include the ACR, blood pressure, glycaemia, medicines and the trend over time. The dispute is about the label (whether to call it CKD), not about whether kidneys need looking after.

Check your profile

Not sure which supplements actually make sense for you?

Answer a few short questions about your lifestyle, diet, sleep, and goals. VitMode will build your profile and show supplements worth considering — with reasoning and evidence strength.

Takes about 2 minutesBased on scientific evidence

Find supplements for me

Recommendations take your answers and the strength of the scientific evidence into account. A supplement's popularity has no bearing on whether it gets recommended.

When a fall in eGFR is a problem: warning signs

When to see a doctor

A result that calls for a conversation with your doctor

An eGFR below 60 ml/min/1.73 m² on at least two tests more than 3 months apart
Protein or blood in the urine, or an ACR above 30 mg/g, regardless of age (see our articles on albuminuria and hematuria)
A clearly lower eGFR than would be expected at that age, for example a value of about 60 in someone in their forties
A rapid fall between successive tests: the KDIGO guidance describes rapid progression as a sustained decline of more than 5 ml/min/1.73 m² per year
A sudden fall after an infection, dehydration, a new drug (especially non-steroidal anti-inflammatory drugs) or contrast, which needs prompt assessment
Coexisting hypertension, diabetes, obesity, cardiovascular disease or a family history of kidney disease
Symptoms: swelling, foamy urine, marked fatigue, a change in the amount of urine

Note that the 2024 KDIGO guideline on the evaluation and management of chronic kidney disease remains based on fixed thresholds and on the combined assessment of eGFR and albuminuria. Large meta-analyses show that mortality risk rises with an eGFR below 60 and with an ACR from about 10 mg/g, independently of each other. Even if part of the decline is 'age-related', it deserves monitoring, because the same result at population level is associated with a statistically higher risk.

What can slow the decline? Levels of evidence

Honesty requires saying that no intervention has been shown to halt kidney ageing in healthy people. We do have good evidence on factors that speed the decline, and more modest evidence on what slows it.

Factor	Nature of the evidence	Notes
Blood pressure control	Randomised and observational studies	In SPRINT, intensive blood pressure lowering caused an early, hemodynamic fall in eGFR that did not weaken the cardiovascular benefit; individual assessment by a doctor
Glycaemic control in people with diabetes	Guidelines and clinical trials	Reduces the risk of kidney complications; applies to people with diabetes, not healthy people
High cardiorespiratory fitness	Preliminary observational data	In a cohort of 198 people with preserved kidney function, higher fitness was associated with slower decline in cystatin C eGFR, but not creatinine
Not smoking, maintaining a healthy body weight	Observational and mechanistic data	Widely recommended; no large interventional trials for the kidneys alone in healthy people
Avoiding long-term use of non-steroidal anti-inflammatory drugs and dehydration	Mechanistic reasoning, clinical practice	These drugs can worsen renal blood flow; decisions on medicines belong to the doctor
'Kidney' supplements	No reliable evidence	No evidence they slow GFR decline in healthy people

What can influence the rate of eGFR decline

What does the research say?

Cardiorespiratory Fitness and Age-Related Decline in Kidney Function among Individuals with Preserved Kidney Health: The Aging Kidney Study

Yoshikoshi S, Kosaki K, Mori S et al. · Med Sci Sports Exerc · 2026

Study findings

A prospective cohort of 198 people (median age 61.4 years, 74% women) with preserved kidney function in whom cardiorespiratory fitness was assessed in a submaximal exercise test and kidney function was measured annually for 5 years (eGFR from cystatin C and from creatinine). Higher fitness was associated with slower decline in cystatin C eGFR (β = 0.011; 95% CI 0.002-0.020) and with a lower risk of rapid decline (OR 0.86; 95% CI 0.75-0.99). This association was not observed for creatinine-based eGFR. The study is observational and small, so it does not prove causality.

Early-stage evidenceView the study on PubMed

This describes what the study found. Editorial interpretation follows in the text below.

Similar caution applies to protein: for healthy people there is no evidence that high protein intake harms in the short term, and long-term data are limited; we describe this more fully in our article on protein and the kidneys. A too-strong belief that 'a diet will slow my GFR decline' has so far no footing in hard data.

Myths and facts about eGFR decline with age

Myth

Since eGFR falls with age in everyone, a result below 60 after seventy can be ignored.

Fact

The decline is common but not neutral: in large analyses the risk of cardiovascular events, kidney failure and death rises with a lower eGFR in older people too, especially when albuminuria coexists. Even proponents of age-based thresholds stress the need for individual risk assessment, not neglect.

Myth

If the creatinine in my results does not change, my kidneys are not ageing.

Fact

Creatinine depends on muscle mass, which declines with age, so a stable creatinine can mask a fall in filtration. Donor studies show a steady loss of functioning nephrons with age. It is worth looking at the eGFR trend calculated by the same equation, at the ACR and, when justified, at cystatin C.

Limitations and summary

Question	Short answer
Does GFR fall with age in healthy people?	Yes, on average from a fraction to about 1 ml/min/1.73 m² a year, with the decline accelerating in older age
Why?	Loss of nephrons: in donors aged 70-75 about 48% fewer non-sclerotic glomeruli than at 18-29
Is a threshold of 60 right for everyone?	Disputed: some experts propose age-based thresholds, others warn against underrating risk in older people
When is it a problem?	Persistent eGFR below 60, albuminuria or blood in the urine, rapid decline, a result unusually low for age
What may slow the decline?	Blood pressure and glycaemic control, not smoking; preliminary data on cardiorespiratory fitness
Do supplements help?	No reliable evidence in healthy people

eGFR and age at a glance

Our editorial recommendation

If in your forties your eGFR is a few points lower than a decade ago, there is no reason to panic: it falls within the typical rate of ageing. Do take care of three things, though: once a year measure your blood pressure and check the ACR (especially with diabetes, hypertension or obesity), compare eGFR over time using the same equation and the same laboratory, and report sudden changes to your doctor. These, and not a single number on a printout, decide whether your kidneys are ageing at a normal pace.

Kidneys age in everyone, but not everyone ages them equally fast. The good news is that we have real influence over several of the factors that set the pace.

VitMode editorial team

Frequently asked questions

It depends on the population and method. In a large Japanese cohort of people aged 40+ the mean decline was 0.36 ml/min/1.73 m² a year; in an old American study of healthy men creatinine clearance fell from 140 to 97 ml/min/1.73 m² between ages 30 and 80 (about 0.9 ml/min a year by our calculation); and in very old people with measured GFR the decline was about 1.05 ml/min a year. People with hypertension or proteinuria lose filtration faster.

There is no single, universally accepted table. Typically healthy young adults have an eGFR of about 90-120, and values gradually fall with age. The KDIGO guidelines use a fixed threshold of 60 ml/min/1.73 m² to diagnose chronic kidney disease (together with an assessment of albuminuria and duration), but the discussion about age-based thresholds continues. The result should be assessed together with the ACR, blood pressure and the trend.

Formally, a value below 60 persisting beyond 3 months meets the criterion for chronic kidney disease under current guidelines, but some experts consider this natural ageing in healthy older people and propose age-based thresholds. At the same time, large analyses show that in older people with an eGFR of 45-59 the risk is raised. Individual assessment (ACR, blood pressure, glycaemia, trend) is therefore needed.

There is no method that stops kidney ageing. You can, however, limit factors that speed the decline: control blood pressure and glycaemia, do not smoke, keep a healthy body weight and avoid overusing kidney-damaging drugs. Preliminary observational data suggest a benefit from higher cardiorespiratory fitness, but they do not prove causality.

eGFR equations take age into account: at the same creatinine concentration an older person has a lower calculated eGFR. In addition, muscle mass declines with age, which lowers creatinine production and can mask a fall in filtration. So compare results calculated by the same equation and, if in doubt, consider cystatin C or the ACR.

The KDIGO guidance describes rapid progression as a sustained decline of more than 5 ml/min/1.73 m² a year. In population studies the average rate is far lower, a fraction to about 1 ml/min a year, so a rapid fall stands out from the norm and needs medical assessment, especially with proteinuria or hypertension.

A preliminary observational study of 198 people with preserved kidney function found that higher cardiorespiratory fitness was associated with slower decline in cystatin C eGFR, but not in creatinine eGFR. That is not proof of causality, but physical activity is recommended for blood pressure, glycaemia and cardiovascular risk, which affect the kidneys indirectly. Remember that very intense exertion just before a test can temporarily change urine results.

Sources (11)

Sources are numbered. PubMed items are automatically verified (identifier, title, year).

Redakcja VitMode — Hormony i endokrynologia

VitMode editorial team — no individual bylines; content based on primary sources

VitMode Editorial — Hormones and Endocrinology is the VitMode editorial team responsible for: hormones, testosterone therapy, the thyroid and metabolism. The team has no individual bylines — texts are prepared by VitMode editors from primary sources (clinical trials, meta-analyses, guidelines). Every cited PubMed paper is automatically checked for a matching identifier, title and publication year. The content is educational and does not replace medical advice. Factual errors can be reported in a comment under the post or through the contact form; corrections are made by the editorial team.