Iron deficiency raises stroke risk

Iron deficiency may raise stroke risk by increasing the stickiness of small blood cells, an Imperial College London team discovered.

Past studies have shown that iron deficiency, which affects about 2 billion people in the world, may be a risk factor for ischaemic stroke in adults and children. About 15 million people suffer from a stroke each year, and ischaemic stroke, caused when an artery to the brain is blocked, is the most common type.

The research team found that iron deficiency increases the stickiness of small blood cells called platelets, which initiate the blood clotting process when they stick together. Oddly enough, this link between iron deficiency and sticky platelets was first discovered almost 40 years ago, but its role was never studied further until now.

Participants of the new study all had a rare disease called hereditary haemorrhagic telangiectasia (HHT), which often leads to enlarged blood vessels in the lungs. Normal blood vessels act as a blood clot filter, but with this abnormality, clots bypass the filter and can infiltrate the brain. Results showed patients with low iron levels were more likely to have a stroke, and that their platelets clumped together more quickly when blood clotting was stimulated.

Patients with another form of abnormal blood vessels, known as pulmonary arteriovenous malformations, were also studied. In this group, even a moderately low iron level doubled their risk of stroke compared to participants with normal iron levels.

Dr. Claire Shovlin from the National Heart and Lung Institute at Imperial College London said this research lights the path toward further analysis.

"The next step is to test whether we can reduce high-risk patients' chances of having a stroke by treating their iron deficiency," she said in a press release. "We will be able to look at whether their platelets become less sticky. There are many additional steps from a clot blocking a blood vessel to the final stroke developing, so it is still unclear just how important sticky platelets are to the overall process. We would certainly encourage more studies to investigate this link."