Kidneys are extraordinarily resilient organs that filter all the blood the heart pumps (just over 52 gallons daily). Each kidney has a higher capacity for purification than is ordinarily required. Even if a person loses one of their two kidneys, the remaining kidney becomes larger and purifies more blood.
However, some chronic health conditions, autoimmune disorders, injuries, infections, and toxins can severely damage the kidneys over time reducing the kidneys’ function to a fraction of their capacity and even causing kidney failure.
Causes of kidney disease
1. Diabetes
Diabetes and chronic kidney disease are connected through two-way interactions where both diseases exacerbate each other. In both type 1 and type 2 diabetes, the excess blood sugar damages the kidneys over time. Diabetes is a top risk factor for kidney disease, and diabetic nephropathy (kidney damage associated with diabetes in 20-40% of diabetics) is a significant cause of end-stage renal disease.
In a diabetic state, excess sugar accumulates in the blood due to insufficient insulin sensitivity or secretion. Excess sugar makes the blood denser and stickier, which can damage the kidneys’ complex network of small blood vessels that purify blood, exchange electrolytes, supply oxygen, and reabsorb water.
Different metabolic pathways link excess sugar with oxidative stress, DNA damage, and persistent inflammation in the kidneys. Excess blood glucose is metabolized into sorbitol which causes osmotic stress and oxidative damage, and is one of the primary mechanisms that injure renal cells. Another class of metabolites synthesized in a high-sugar environment are advanced glycation end-products that accumulate in renal tissues and bind to cell receptors activating pathways for inflammation and cell fibrosis.
Kidney disease on the other hand can also cause or exacerbate diabetes. Kidneys filter blood and absorb sugar as needed. When kidneys lose their function, they adversely affect glucose metabolism which can cause impaired glucose sensitivity and the development of insulin resistance (as seen in Type 2 diabetes). It brings individuals “closer to” the diabetic state.
Unsurprisingly, as diabetes is increasing around the world, so is chronic kidney disease. Both diabetes and chronic kidney disease have concurrently become global epidemics.
2. High blood pressure
Like diabetes, high blood pressure has a two-way interaction with kidney disease. Each condition exacerbates the other. In high blood pressure, blood vessels in the whole body including the kidneys can constrict and get damaged. Constant strain from uncontrolled high blood pressure weakens the blood vessels and reduces blood flow. Damaged blood vessels and reduced blood flow through the kidneys result in a decreased volume of blood filtered. Damaged kidneys result in extra fluid building up in the body, increasing blood pressure even more.
3. Obesity
Obesity increases the risk of chronic kidney disease through many different mechanisms. Obesity increases the risk of both diabetes and high blood pressure which independently increase the risk of kidney disease. Being obese or overweight also physically changes the kidneys, causing hemodynamic, structural, and histological alterations in the kidney tissues that can make the kidneys more prone to damage.
4. Age over 60
Natural aging of the kidneys reduces kidney function. According to the CDC, kidney filtration declines by about 1% every year after age 40. That means a loss of about 18% by the time we are 60, and 33% by the time we are 80. Older individuals are also more likely to have accumulated more damage from other conditions such as diabetes and high blood pressure.
5. Genetics
Some genetically inherited conditions can cause severe kidney disease at different stages of life. Even in the absence of other risk factors some of them can rapidly bring the patient to end-stage kidney disease (ESKD) when dialysis or kidney transplant becomes crucial to save life.
- Autosomal Dominant Polycystic Kidney Disease. Autosomal dominant polycystic kidney disease is caused by one of two mutations in genes PKD1 and PKD2. PKD1 mutation occurs 85% of the time, has more severe symptoms, and causes kidney failure after age 60. PKD2 mutation is less common, has less severe symptoms, and can cause kidney failure after age 70. These two mutations combined are the most common genetic cause of ESKD, accounting for 5-10% of all cases of ESKD.
- Autosomal Recessive Polycystic Kidney Disease. Autosomal recessive polycystic kidney disease is a rare disease that affects infants and children. About half of the patients with the disease progress to ESKD in early childhood. In the general population, the disease affects 1 in 20,000 individuals. When a parent has autosomal recessive polycystic kidney disease, the estimated risk of their children inheriting it is 1 in 140.
- Nephronophthisis. Nephronophthisis is a rare genetic kidney disease that affects 1 in 922,000 individuals in the US. The disease can lead a patient to ESKD in their 30s.
6. History of kidney injury
Kidneys can be injured by infections, certain drugs or medications, and restrictions in blood flow such as during a shock. Acute kidney injury often happens in a hospital setting when patients are receiving critical care. Acute kidney injuries weaken the kidneys and sometimes result in chronic kidney disease.
7. Cigarette smoking
Cigarette smoking is an independent risk factor for chronic kidney disease. It can cause kidney disease, exacerbate existing kidney disease, and shorten kidney transplant graft survival.
8. Autoimmune disease
In systemic autoimmune diseases such as lupus, the body’s immune system mistakenly attacks healthy tissues. Such disorders can damage the kidneys over time resulting in chronic kidney disease.
The information provided in our blog posts is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.