Kidney disease is most often caused by other conditions that put a strain on the kidneys.

High blood pressure (hypertension) and diabetes are the most common causes of kidney disease. The evidence indicates that high blood pressure causes just over a quarter of all cases of kidney failure. Diabetes has been established as the cause of around a quarter of all cases.

High blood pressure

Blood pressure is a measure of the pressure your heart generates in your arteries with each pulse. Too much pressure can damage your body's organs, leading to heart disease, stroke and worsening of kidney function.

The cause of around 90% of cases of high blood pressure is unknown, although there appears to be a link between the condition and a person’s general health, diet, and lifestyle.

Known risk factors for high blood pressure include:

• age (the risk of developing high blood pressure increases as you get older) 
• family history of high blood pressure (the condition seems to run in families) 
• being of African-Caribbean or south Asian origin 
• obesity 
• lack of exercise 
• smoking
• excessive alcohol consumption 
• high amount of salt in your diet
• high-fat diet 
• stress

Hypertension causes damage by putting strain on the small blood vessels in the kidneys. This prevents the filtering process from working properly.

Diabetes

Diabetes is a condition in which the body produces no – or too little – insulin (type 1 diabetes) or has become unable to make effective use of insulin (type 2 diabetes).

Insulin is needed to regulate levels of glucose (sugar) in your blood, preventing the levels going too high after a meal and too low between meals.

If diabetes is poorly controlled, too much glucose can build up in your blood. The glucose can damage the tiny filters in the kidneys, which affects the ability of your kidneys to filter out waste products and fluids.

It is estimated that 20-40% of people with type 1 diabetes will develop kidney disease before they reach 50 years of age. Around 30% of people with type 2 diabetes also show signs of developing kidney damage.

The first sign of diabetic kidney disease is the appearance of low levels of protein in the urine. Therefore, your GP will ask for an annual urine test so any kidney disease can be detected as early as possible.

All people with diabetes should have a kidney check every year. Early detection of kidney dysfunction in diabetes is important because it identifies people at risk or complications, such as eye problems and impotence.

Other causes

There are many other conditions that less commonly cause CKD, including:

• glomerulonephritis (inflammation of the kidney) 
• pyelonephritis (infection in the kidney) 
• polycystic kidney disease (an inherited condition where both kidneys are larger than normal due to the gradual growth of masses of cysts) 
• failure of normal kidney development in an unborn baby while developing in the womb
• systemic lupus erythematosus (a condition of the immune system where the body attacks the kidney as if it were foreign tissue)
• long-term, regular use of medicines, such as lithium and non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin and ibuprofen   
• blockages, for example due to kidney stones or prostate disease