What is the normal age related decline in eGFR?

After age 30, the kidneys begin a slow, natural decline in function, a key aspect of healthy aging. Understanding what is the normal age related decline in eGFR is crucial for distinguishing between this physiological process and the onset of disease.

Quick Summary

The normal age-related decline in estimated glomerular filtration rate (eGFR) is a gradual process, typically averaging about 1 mL/min/1.73 m² per year after age 30. This decline is a normal part of aging, but a more rapid decrease can signal an underlying health issue.

Key Points

• Normal Decline Rate: On average, eGFR declines by about 1 mL/min/1.73 m² per year after age 30.

• Not Always a Disease: A lower eGFR in an older person needs medical monitoring.

• Risk Factors Accelerate Decline: Conditions like high blood pressure and diabetes cause a faster decline than normal aging.

• Lifestyle Management is Key: Healthy habits like managing blood pressure and exercising help preserve kidney function.

• CKD vs. Aging: CKD differs from normal aging by a faster eGFR loss, kidney damage signs, and higher health risks.

• Regular Monitoring is Essential: Early detection through eGFR tests is critical for slowing disease progression.

Understanding eGFR and Kidney Function

eGFR, or estimated glomerular filtration rate, indicates how well your kidneys filter waste from your blood. It is calculated using your blood creatinine level, age, sex, and other factors. A lower eGFR can suggest reduced kidney function. The eGFR calculation was updated in 2021 by the National Kidney Foundation and the American Society of Nephrology to remove race as a factor. While generally reliable, eGFR can be less accurate in certain individuals, such as those with unusual muscle mass or during pregnancy.

The Normal Rate of Age-Related Decline

Kidney function typically peaks in early adulthood and begins to decline after age 30-40. A normal rate of decline is often around 1 mL/min/1.73 m² per year. This rate varies among individuals and may accelerate after age 50 or 60. This gradual decline is thought to be due to normal changes in the kidney, including a decrease in filtering units called nephrons.

eGFR Levels by Age: A General Guide

Average eGFR values change with age. These figures provide a general context, but individual results can vary. A low eGFR in an older person needs medical evaluation.

Age Group	Average eGFR (mL/min/1.73 m²)
20s	116
30s	107
40s	99
50s	93
60s	85
70+	75

Differentiating Normal Aging from Chronic Kidney Disease (CKD)

A persistent eGFR below 60 mL/min/1.73 m² for three or more months indicates chronic kidney disease. CKD involves a faster and more severe decline in kidney function than normal aging. Key distinctions include: a faster rate of decline than typical aging, more significant damage to kidney tissue, often the presence of protein in urine, and higher health risks.

Factors that Accelerate Kidney Function Decline

Certain factors can speed up kidney function decline. Managing these is important for maintaining kidney health.

Modifiable Risk Factors

• Hypertension (High Blood Pressure): A major contributor to kidney disease.
• Diabetes: Poor blood sugar control damages kidney filters.
• Smoking: Damages kidney blood vessels.
• Obesity: Linked to faster kidney function loss.
• Lifestyle: Poor diet, inactivity, and excessive alcohol can harm kidneys.
• Certain Medications: Overuse of NSAIDs can be harmful.

Non-Modifiable Factors

• Cardiovascular Disease: Associated with declining kidney function.
• Genetics: Family history of CKD increases risk.

For more information on kidney health, visit the American Kidney Fund.

Strategies to Support Kidney Health

While some decline is normal, you can take steps to protect your kidneys:

1. Manage Health Conditions: Control blood pressure and blood sugar if you have hypertension or diabetes.
2. Healthy Lifestyle: Maintain a healthy weight, exercise, and eat a low-sodium diet.
3. Stay Hydrated: Drink enough water.
4. Avoid Smoking: Quitting benefits kidney health significantly.
5. Use Medications Wisely: Follow medical advice for all medications.
6. Regular Monitoring: Get regular tests if you have risk factors.

Conclusion: The Importance of Monitoring Kidney Function

The normal age-related decline in eGFR is a natural process, but it's important to monitor kidney function, especially in older adults. Understanding the typical rate of decline and identifying risk factors that can speed it up allows for proactive steps to protect renal function. Regular eGFR and urine tests can detect CKD early, enabling lifestyle changes and medical treatment to slow progression and prevent complications.

Frequently Asked Questions

What is eGFR and how is it tested?

eGFR stands for estimated glomerular filtration rate. It's a measure of how well your kidneys filter waste from your blood. It is calculated using a simple blood test that measures creatinine levels, along with your age and sex.

Is a lower eGFR in older adults always a sign of chronic kidney disease?

Not necessarily. While eGFR naturally decreases with age, a low eGFR in an older person doesn't automatically mean they have CKD. The diagnosis requires the eGFR to be below 60 mL/min/1.73 m² for three or more months, and a doctor will look for other signs of kidney damage.

What is the average rate of eGFR decline with age?

For most people, the decline in eGFR starts after age 30 and proceeds at an average rate of about 1 mL/min/1.73 m² per year.

What factors can speed up the age-related decline in eGFR?

Factors that can accelerate eGFR decline include uncontrolled high blood pressure, diabetes, smoking, obesity, cardiovascular disease, and overuse of certain medications.

Can I slow down the natural decline of my kidney function?

Yes. By managing risk factors, you can help preserve kidney health. Key strategies include controlling blood pressure and blood sugar, eating a healthy diet, exercising regularly, and not smoking.

How often should I have my eGFR tested?

The frequency of eGFR testing depends on your age, risk factors, and overall health. If you are at risk for kidney disease due to conditions like diabetes or high blood pressure, your doctor may recommend regular screening.

What lifestyle changes are most beneficial for supporting kidney health?

Maintaining a healthy weight, exercising regularly, and following a diet low in sodium are among the most beneficial lifestyle changes. Additionally, staying well-hydrated and avoiding smoking are crucial.