Peripheral vascular disease (PVD) is usually caused by a build-up of fatty deposits on the walls of the arteries inside the legs. The fatty deposits, called 'atheroma', are made up of cholesterol and other waste substances.
The build-up of atheroma on the walls of the arteries makes the arteries narrower and restricts the flow of blood to the legs. This process is called 'atherosclerosis'.
People with PVD can experience painful cramps in their leg muscles during physical activity because the muscles are not receiving the blood supply that they need.
Like all tissue in your body, the muscles in your legs need a constant supply of blood to function properly. When you are using your leg muscles, the demand for blood increases tenfold. But if the arteries in your legs are blocked, the supply of available blood cannot meet the demand.
This shortfall between supply and demand causes your muscles to experience painful cramps, which only get better after you rest your legs.
Risk factors for PVD
Over time as you get older, your arteries naturally begin to harden and get narrower, which can lead to atherosclerosis and then PVD.
However, there are many factors that can dangerously speed up this process. These are described below.
The single most important risk factor for PVD is smoking. Smoking can damage the walls of your arteries. Tiny blood cells, known as 'platelets', will then collect at the site of the damage to try to repair it. This can cause your arteries to narrow.
It is estimated that smokers are six times more likely to develop PVD than non-smokers and more than 80% of people who develop PVD are current or former smokers.
If you have poorly controlled type 1 or type 2 diabetes, the excess glucose in your blood can damage your arteries.
People with diabetes are two to four times more likely to develop PVD, and having a combination of poorly controlled diabetes and PVD is a major risk factor for amputation. People with diabetes and PVD are 15 times more likely to need an amputation than people with PVD who do not have diabetes.
High-fat diets and cholesterol
Cholesterol is a type of fat that is essential for the body to function. Cholesterol helps to produce hormones, to make up cell membranes (the walls that protect individual cells) and to protect nerve endings.
Cholesterol cannot travel around the body on its own because it does not dissolve in water. Instead, it is carried in your blood by molecules called 'lipoproteins'.
The two main lipoproteins are LDL and HDL:
- Low-density lipoprotein (LDL) is the main cholesterol transporter and carries cholesterol from your liver to the cells that need it. If there is too much cholesterol for the cells to use, this can cause a harmful build-up in your blood and lead to atherosclerosis. For this reason, LDL cholesterol is known as 'bad cholesterol', and lower levels are better for your health.
- High-density lipoprotein (HDL) carries cholesterol away from the cells and back to the liver, where it is either broken down or passed from the body as a waste product. For this reason, it is referred to as 'good cholesterol', and higher levels are better for your health.
Most of the cholesterol that your body needs is made by your liver. However, if you eat foods that are high in saturated fat, the fat is broken down into LDL ('bad cholesterol').
Blood cholesterol is measured in units called millimoles per litre of blood, often shortened to mmol/L. It is estimated that the risk of developing PVD increases by 10% for each 0.25 mmol/L rise in your cholesterol levels.
High blood pressure
Your arteries are designed to pump blood at a certain pressure, and if blood pressure is very high (known as 'hypertension'), the walls of the arteries can become damaged. High blood pressure can be caused by:
Homocysteine is a type of amino acid (molecule that makes up protein) found in the blood. Research has found that 30-40% of people with PVD have above average levels of homocysteine in their blood. And 1 in 4 people who develop leg pain have extremely high levels.
It has been suggested that high levels of homocysteine may damage the walls of the arteries, leading to atherosclerosis, but this has not been proven.
Vitamin B supplements and eating foods high in folic acid, such as green leafy vegetables or wholegrains, are known to lower homocysteine levels. However, researchers found no significant reduction in risk of cardiovascular disease when people with PVD increased the amount of vitamin B and folic acid in their diet.
Source: NHS Choices, UK (Causes of peripheral arterial disease)
Last reviewed: September 2015