Iron deficiency increases stroke risk by making blood sticky

More than 15 million people worldwide suffer a stroke every year, resulting in almost 6 million deaths. Now, new research from Imperial College London in the UK finds that iron deficiency could increase a person's risk of stroke by making the blood sticky.

The research team notes that previous research has shown that iron deficiency could be a risk factor for ischemic stroke - when small blood clots interrupt blood flow to the brain - in adults and children.

To investigate why this is the case, the researchers analyzed the iron levels of 497 patients with hereditary hemorrhagic telangiectasia (HHT) - a rare disease than can lead to enlarged blood vessels in the lungs.

The research team explains that healthy blood vessels usually filter out small blood clots before the blood travels to the arteries. But in HHT, the blood vessels can allow small blood clots to make their way to the brain.

The investigators found that patients with moderately low iron levels (6 micromoles per liter) had double the risk of stroke, compared with patients with iron levels deemed middle of the normal range (7-27 micromoles per liter). Further investigation revealed that iron deficiency increases the stickiness of platelets - small blood cells. This prompts platelets to stick together, causing clotting.

Since platelets in the blood stick together more if you are short of iron, this may explain why being short of iron can lead to strokes, though much more research will be needed to prove this link. The research team plans to investigate whether treating iron deficiency in high-risk patients could reduce their risk of stroke, and specifically, whether this would cause platelets in the blood to become less sticky.