Kidney disease develops when something damages the small blood vessels and filtering units inside your kidneys, and the two most common culprits are diabetes and high blood pressure. About 1 in 7 U.S. adults, roughly 37 million people, are living with chronic kidney disease, and many don’t know it because early stages rarely cause symptoms. The causes range from long-term conditions that slowly wear kidneys down over years to sudden injuries, genetic conditions, and even everyday medications.
Diabetes and High Blood Sugar
Diabetes is the single leading cause of kidney disease. Your kidneys contain millions of tiny blood vessel clusters called glomeruli that filter waste from your blood. When blood sugar stays elevated over months and years, it damages those delicate vessels and causes scarring. Once scar tissue replaces healthy filtering tissue, that portion of the kidney stops working permanently. The damage tends to build quietly. You can lose a significant amount of kidney function before any symptoms appear, which is why routine urine and blood tests matter if you have diabetes.
High Blood Pressure
High blood pressure is the second most common cause, and it creates a vicious cycle: it damages kidneys, and damaged kidneys raise blood pressure further. Normally, your kidneys’ blood vessels automatically adjust to protect the delicate filtering structures from spikes in pressure. When blood pressure stays chronically high, that protective mechanism gets overwhelmed. Elevated pressure pushes through to the tiny vessels inside the kidney, gradually thickening and narrowing them. Over time, less blood reaches the filtering units, and kidney function declines.
When blood pressure is extremely high, the damage can be more sudden and severe, causing acute injury to both blood vessels and glomeruli rather than the slow scarring seen with moderately elevated pressure.
Autoimmune and Inflammatory Conditions
Your immune system can turn against your kidneys in several ways, all grouped under the term glomerulonephritis, which means inflammation of the kidney’s filters.
- Lupus is a chronic inflammatory disease that can attack many organs, including the kidneys. Lupus nephritis is one of the more common autoimmune causes of kidney failure.
- IgA nephropathy occurs when a type of antibody called immunoglobulin A builds up inside the glomeruli. The resulting inflammation can go undetected for years because it often causes no pain or obvious symptoms.
- Goodpasture’s syndrome is a rare condition in which the immune system creates antibodies that specifically target tissue in the kidneys and lungs, causing progressive and sometimes permanent damage.
- Vasculitis involves inflammation of blood vessels throughout the body, including those in the kidneys. Several forms exist, including granulomatosis with polyangiitis and polyarteritis, both of which can severely impair kidney function.
These conditions vary widely in severity. Some respond well to treatment and cause minimal long-term damage, while others can lead to kidney failure if not caught early.
Genetic and Inherited Causes
Polycystic kidney disease (PKD) is the most well-known inherited form. It causes fluid-filled cysts to grow throughout the kidneys, gradually crowding out healthy tissue. Two types exist, and they follow different inheritance patterns.
The more common form, autosomal dominant PKD, requires only one copy of a mutated gene (PKD1 or PKD2) from one parent. A person born with this mutation will develop cysts, though the rate of progression varies. Mutations in the PKD1 gene tend to cause more severe disease than PKD2 mutations. The rarer form, autosomal recessive PKD, requires two copies of a mutated gene (PKHD1), one from each parent. This type typically appears in infancy or childhood and is more immediately serious.
Other inherited conditions, including Alport syndrome and Fabry disease, can also lead to kidney damage, though they are less common.
Medications That Harm the Kidneys
Common over-the-counter pain relievers like ibuprofen and naproxen (NSAIDs) can damage your kidneys, especially with high cumulative doses over long periods. These drugs work by reducing blood flow to parts of the body, including the kidneys. For most healthy people, occasional use is fine. The risk climbs when you take them frequently, use them alongside blood pressure medications or diuretics, or already have reduced kidney function. Combining NSAIDs with those other drugs is particularly risky within the first 30 days of starting the combination.
Certain prescription medications, some antibiotics, and contrast dyes used in imaging scans can also stress the kidneys. If you take pain relievers regularly for a chronic condition, it’s worth knowing your kidney function through a simple blood test.
Urinary Tract Blockages
Physical obstructions in the urinary tract can cause kidney damage from the outside in. Kidney stones, an enlarged prostate, tumors, or structural abnormalities can prevent urine from draining properly. When urine backs up toward the kidneys, it causes swelling called hydronephrosis. If the blockage isn’t relieved, that sustained pressure can eventually cause the kidneys to stop working. This type of damage is often reversible if the obstruction is found and treated before permanent injury sets in.
Acute Kidney Injury
Not all kidney disease develops slowly. Acute kidney injury happens when the kidneys suddenly lose their ability to filter waste, often over hours or days. Common triggers include severe dehydration, major blood loss, serious infections (especially sepsis), heart failure, liver failure, and severe allergic reactions. Certain medications and toxins can also cause it.
The encouraging part: acute kidney injury can often be reversed. People who were otherwise healthy before the event frequently recover most or all of their kidney function. However, repeated episodes of acute injury or a single severe episode can leave lasting damage that raises the risk of chronic kidney disease later.
Smoking, Obesity, and Other Lifestyle Factors
Smoking is an independent risk factor for kidney disease, separate from its effects on blood pressure. A large meta-analysis of prospective studies found that current smokers had a 34% higher risk of developing chronic kidney disease compared to people who never smoked. For the most severe outcome, end-stage kidney failure requiring dialysis or transplant, current smokers faced a 91% higher risk. Former smokers still carried elevated risk, but significantly less than active smokers, suggesting that quitting provides real benefit.
Obesity contributes to kidney disease both directly and by fueling diabetes and high blood pressure. Excess body weight forces the kidneys to work harder to filter blood, and over time that extra workload damages the filtering units. A high-sodium diet, chronic dehydration, and excessive alcohol use also put added strain on the kidneys, though their effects are harder to quantify individually.
Repeated Infections and Other Causes
Chronic or recurrent kidney infections can scar kidney tissue over time, especially if infections go untreated or are incompletely treated. Conditions that cause frequent urinary tract infections, such as structural abnormalities or vesicoureteral reflux (where urine flows backward from the bladder to the kidneys), raise the long-term risk.
Some less common causes include sickle cell disease, HIV, hepatitis B and C, and cancers that either originate in or spread to the kidneys. In some cases, no single cause is identified, particularly in older adults where years of mild, overlapping risk factors accumulate.
Why Early Detection Matters
Most of these causes share one frustrating feature: they damage the kidneys silently. You can lose up to 70-80% of kidney function before feeling noticeably unwell. Two simple tests, a blood test measuring creatinine (which estimates your filtration rate) and a urine test checking for protein, can catch kidney disease years before symptoms develop. If you have diabetes, high blood pressure, a family history of kidney disease, or you’re over 60, regular screening gives you the best chance of catching damage while it’s still manageable.