Blood clots are a serious health problem that affect millions of people around the world every year.
While blood clotting is a normal process that helps stop bleeding after an injury, clots that form inside blood vessels can become life-threatening.
If a clot blocks blood flow or travels to the lungs, it can cause severe illness or even death. A new study from Sweden has now uncovered three common genetic changes that can greatly increase a person’s risk of developing blood clots in the legs, offering new clues about who may be most at risk.
The research was carried out by scientists at Lund University and was published in the Journal of Thrombosis and Haemostasis. The researchers found that certain inherited gene variants can significantly increase the chance of developing venous thrombosis, also called venous thromboembolism.
This condition happens when a blood clot forms in a vein, most often in the deep veins of the legs. If part of the clot breaks away and travels to the lungs, it can block blood flow and cause a dangerous condition known as pulmonary embolism.
Blood clots can develop in either arteries or veins, but the causes are different. Arterial clots usually form after fatty plaque inside an artery breaks open, triggering the body’s clotting system.
These clots can lead to heart attacks and strokes. Venous clots usually develop when blood moves too slowly through the veins. This slower blood flow allows the clotting system to become active, causing a clot to form.
Although venous blood clots are one of the leading causes of death worldwide, they often receive less public attention than heart attacks or strokes. In Sweden alone, more than 10,000 people develop venous thromboembolism each year. The risk becomes higher as people grow older.
Obesity also increases the risk because extra body weight can reduce healthy blood flow through the veins. Taller people are also more likely to develop clots because blood has farther to travel from the legs back to the heart, making blood flow slower.
Lifestyle also plays an important role. Long periods of sitting, such as during long-distance flights or recovery after surgery, can slow blood circulation and increase the chance of a clot forming.
Pregnancy raises the risk because natural changes in the body increase clotting factors while reducing some protective proteins. Doctors often prescribe blood-thinning medicines for people at high risk during these situations.
Diet may also influence clot risk. Growing evidence suggests that eating large amounts of ultra-processed foods may slightly increase the risk, while diets rich in vegetables, fruits, whole grains, legumes, fish, and other healthy foods may help lower it.
Researchers have even observed that commercial fishermen appear to have fewer blood clots, possibly because they regularly consume fish rich in omega-3 fatty acids.
Genes are another important part of the picture. One well-known inherited mutation called Factor V Leiden has long been linked to blood clots, especially among people of European ancestry. However, the new study discovered three additional gene variants that may affect people around the world.
The researchers studied genetic information from about 30,000 people who participated in the Malmö Diet and Cancer Study. They examined 27 genes involved in blood clotting.
Three gene variants, known as ABO, F8, and VWF, each increased the risk of blood clots by about 10% to 30%. People who carried five of these risk-related genetic changes had up to a 180% higher risk of developing venous blood clots.
Unlike Factor V Leiden, which is mainly found in Europeans, these newly identified variants are common in many populations worldwide. This means the findings could benefit people across many different countries.
Researchers now hope to study whether the number of clotting-related genes a person carries should help doctors decide how long blood-thinning treatment should continue after someone experiences a blood clot.
Although you cannot change your genes, there are many ways to lower your overall risk. Staying physically active, avoiding long periods of sitting, maintaining a healthy weight, eating a balanced diet, not smoking, following medical advice after surgery, and taking prescribed blood-thinning medicines when needed can all help reduce the chance of dangerous blood clots.
This research gives scientists a better understanding of why some people develop blood clots while others do not. In the future, genetic testing may help identify people at higher risk so they can receive earlier treatment and better protection from this potentially deadly condition.
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The study was published in the Journal of Thrombosis and Haemostasis.
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