The Link Between Aging and Kidney Function
As people age, it's natural for kidney function to gradually decline [1]. The prevalence of chronic kidney disease (CKD) is significantly higher in older populations, affecting about 34% of those aged 65 and older [1], compared to just 12% of people aged 45–64 and 6% of those aged 18–44 [2]. This increased risk is due to a combination of natural, age-related changes and the accumulation of risk factors over time [1]. The kidneys' filtering units, called glomeruli, can become scarred and less efficient with age [1].
Primary Causes and Major Risk Factors
Diabetes and high blood pressure (hypertension) are the two leading causes of CKD, accounting for nearly two-thirds of all cases [3, 6, 7]. These conditions damage the small blood vessels in the kidneys, impairing their ability to filter waste [3].
Key Risk Factors Include:
- Diabetes: The leading cause [6].
- High Blood Pressure: The second most common cause [6].
- Heart Disease: A strong link exists between heart and kidney health [3].
- Family History: Increases your risk [3].
- Obesity: Contributes to diabetes and high blood pressure [3].
- Older Age: Risk increases significantly after 60 [1].
- Smoking: Damages blood vessels [3].
- Abnormal Kidney Structure: Such as polycystic kidney disease [3].
- Frequent Use of NSAIDs: Can harm kidneys [3].
The 'Silent' Nature of Early-Stage Kidney Disease
Early-stage CKD often has no symptoms [3, 5]. Many people don't realize their kidneys are failing until the disease is advanced [3]. As kidney function declines, symptoms may appear [3, 5], including:
- Fatigue and weakness [3]
- Swelling in the feet and ankles (edema) [3]
- Changes in urination [3]
- Foamy urine (protein sign) [3]
- Muscle cramps [3]
- Dry, itchy skin [3]
- Loss of appetite [3]
Understanding the Stages of CKD
Kidney disease is categorized into five stages based on the estimated glomerular filtration rate (eGFR) [4, 5]. A higher eGFR indicates better kidney function [5].
- Stage 1: eGFR 90 or higher, with other signs of damage [4].
- Stage 2: eGFR 60-89. Mild loss of function [4].
- Stage 3a: eGFR 45-59. Mild to moderate loss [4].
- Stage 3b: eGFR 30-44. Moderate to severe loss; symptoms may appear [4].
- Stage 4: eGFR 15-29. Severe loss; preparation for dialysis/transplant [4].
- Stage 5: eGFR less than 15. Kidney failure requiring dialysis or transplant [4].
Comparison of Top Two Causes: Diabetes vs. Hypertension
| Feature | Diabetes-Related Kidney Disease | Hypertension-Related Kidney Disease |
|---|---|---|
| Primary Mechanism | High blood sugar damages vessels and filtering units [6]. | High pressure damages blood vessels in kidneys [6]. |
| First Sign | Often, albumin in urine (albuminuria) [6]. | Often found through routine checks and tests [6]. |
| Progression | Slowed with tight blood sugar control [6]. | Slowed by managing blood pressure [6]. |
| Prevalence | Approx. 1 in 3 adults with diabetes has CKD [7]. | Approx. 1 in 5 adults with high blood pressure has CKD [7]. |
How to Protect Your Kidneys and Reduce Risk
Proactive steps can protect kidneys and slow CKD progression [1, 3, 5]:
- Manage Blood Pressure and Blood Sugar: Keep them in a target range [3].
- Reduce Salt Intake: Helps control blood pressure [3].
- Stay Hydrated: Drink enough water [3].
- Maintain a Healthy Weight: Through diet and exercise [3].
- Don't Smoke: Improves kidney health [3].
- Use NSAIDs Cautiously: Avoid long-term use unless directed by a doctor [3].
- Get Tested: If over 60 or at risk, ask for annual urine (ACR) and blood (eGFR) tests [1, 3].
For more detailed information, visit the National Kidney Foundation [1].
Conclusion
While CKD can occur at any age, the risk significantly increases after 60 [1]. Due to its often silent early stages, awareness and screening are vital [3]. Managing risk factors like diabetes and high blood pressure, alongside a healthy lifestyle, can help protect kidney health [1, 3].
