The health of your kidneys may actually reveal clues about your risk of developing dementia and cognitive decline.
A study published in Kidney360 from the American Society of Nephrology found mild albuminuria (a type of protein found in urine) was associated with an increased risk of current cognitive impairment in overall cognitive function, memory and processing speed—plus a 19% increased risk of moderate cognitive decline and 32% increased risk of dementia up to five years later.
“The finding of this study is not surprising,” said Dr. Mohamed Atta, MD, MPH, professor of medicine at Johns Hopkins Medicine. “Albuminuria is considered a marker of vascular health, not only in the kidney but elsewhere including the brain.”
What to know about kidney function and albuminuria
Kidneys are vital organs in the body located at the bottom of your rib cage on both sides of the spine that function by filtering waste products, excess water and other contamination from your blood.
Kidneys can also store any waste products in the bladder and later get rid of them through urine. In addition, they’re able to filter blood and keep important nutrients like protein – which help build muscle, repair tissue and fight infection – inside your blood.
However, when kidneys are damaged, protein can “leak” out of the kidneys into your urine, said Dr. S. Adam Ramin, MD, urologist and medical director of Urology Cancer Specialists in Los Angeles.
“Kidneys are like a filter. Filters have small pores that allow certain things to pass through,” Ramin explained. “However, if the kidney has some sort of damage or insufficiency, then those pores may become larger and allow albumin (protein in the blood) to filter through or seep through the porous areas of the kidney into the urine.”
He added when albuminuria occurs, it is generally considered a problem having to do with kidney insufficiency and may lead to kidney failure.
How might kidney health be related to dementia risk and cognitive decline?
According to Ramin, people with albuminuria may have multiple other medical problems which can also lead to dementia. For example, patients with albuminuria are usually patients with long-standing hypertension, coronary artery disease, diabetes and kidney failure.
“All of these medical problems that a person might have in combination, or one alone, may also lead to factors that can cause dementia,” he said.
For instance, a patient with hypertension may develop a small vascular disease inside the brain, causing the small blood vessels in the brain to close up and become atherosclerotic (hardening of the arteries) or stenotic (narrowing of the blood vessels).
When that occurs, it can cause less blood flow to the brain and lead to brain atrophy (a loss of neurons and connections between neurons), which can then cause dementia.
“Similarly, diabetes and coronary artery disease can do that. The factors that lead to kidney failure or kidney insufficiency are the same factors that can also cause brain atrophy and dementia,” Ramin added.
It’s important to note that albuminuria is not the cause of dementia but that the researchers of the study found an association exists.
How can I tell if my kidneys are healthy?
One way to tell if your kidneys are healthy is to take an at-home kidney function test, which Ramin said is typically available for purchase at pharmacies and uses a urine sample to detect the presence of blood or albumin proteins.
However, if this is not available or realistic, patients can see their health care provider for blood tests, urine labs and imaging of the kidneys to help determine kidney health. A biopsy may also be required.
“A kidney function test can check what’s called creatinine, which can also lead to the possibility of any kind of kidney insufficiency or kidney failure,” Ramin said. “In addition to that, we can do blood testing to see how much albumin is in the bloodstream.”
Because albuminuria is easily measured in a primary provider’s clinic, it could be used to identify those at higher risk of current cognitive impairment, decline or dementia.
Unfortunately, because kidney disease is silent unless late in the disease process and may not always present noticeable symptoms during the early stages, many doctors recommend routine yearly physicals, labs and potentially other tests to ensure healthy kidneys.
If albuminuria is found, blood pressure medications are now available that appear to decrease the risk of progression of chronic kidney disease, especially in those with diabetes.
What are the signs of albuminuria and kidney disease?
Only those with advanced disease are expected to have symptoms—many of which are nonspecific, such as low appetite, nausea, poor concentration, decreased mental state, sleep disturbances or skin itching. Most patients with early kidney disease have no symptoms, which is why regular checkups are important, but some symptoms may still be present:
- Frequent urination
- Shortness of breath
- Tiredness
- Vomiting and nausea
- Lack of appetite
- Muscle cramping
- Puffiness around the eyes
- Swelling in the face, belly, feet or ankles
- Nausea and vomiting
- Loss of appetite
- Fatigue and weakness
- Urinating more or less
- Muscle cramps
- Swelling of feet and ankles
- Shortness of breath
- Chest pain
- Foam or blood in the urine
- Dry and itchy skin
Ramin said some of the listed symptoms, including foamy or bloody urine and increased blood pressure (especially due to the use of medications), can be the most common signs of kidney problems in older adults.
If you or a loved one notices or experiences any of these signs or symptoms, immediately contact your health care provider to decide the best course of action and seek treatment.
What can I do to protect my kidneys and keep them healthy?
Jen Hernandez, RDN, CSR, LDN, registered dietitian, recommends the following to keep kidneys healthy:
- Drink plenty of water to clear toxins and sodium.
- Monitor sodium or salt levels in your diet and avoid consuming frequent packaged or restaurant foods.
- Maintain a healthy body weight by having a well-balanced diet of fruits and vegetables, whole grains, legumes and healthy fats.
- Regulate and monitor blood sugar and blood pressure levels.
- Avoid over-the-counter medications or supplements and ensure prescribed medications are appropriate for kidney function.
- Get kidney function tests and urine analysis done regularly with a doctor or nephrologist.
