People with low iron levels in their blood may have a higher risk of dangerous clots.
A study of clotting risk factors in patients with an inherited blood vessel disease suggests that treating iron deficiency could be instrumental in preventing potentially lethal clots.
Deep vein thrombosis -- blood clots that form in the veins -- can cause pain and swelling, but can also be fatal if the clot is dislodged and travels into the blood vessels of the lungs.
To look for new risk factors for blood clots, scientists at Imperial College London studied patients with hereditary haemorrhagic telangiectasia (HHT), the journal Thorax reports.
HHT is an inherited disease of the blood vessels, the main symptoms of which are excessive bleeding from the nose and gut, according to an Imperial College statement.
"Most of our patients who had blood clots did not have any of the known risk factors," said Claire Shovlin, from the National Heart and Lung Institute at Imperial College London, who led the study.
Shovlin and team analysed blood from 609 patients reviewed at the HHT clinic at Imperial College's Hammersmith Hospital from 1999 to 2011, to look for differences between the patients who had blood clots and those who did not.
Many of the patients had low iron levels because of iron lost through bleeding. The researchers found that low levels of iron in the blood were a strong risk factor for blood clots.
Patients who took iron supplements did not have higher risk, suggesting that treatment for iron deficiency can prevent blood clots.
"Our study shows that in people with HHT, low levels of iron in the blood is a potentially treatable risk factor for blood clots," Shovlin said.