New study by researchers from Harvard Medical School has shown that Men who smoke more than 20 cigarettes a day run over twice the risk of a stroke caused by bleeding into the brain. Researchers had already identified a link between ischemic stroke - caused by a clot in a blood vessel serving the brain - and smoking. The new study that covered 22,022 male US physicians followed for nearly 18 years has shown that compared to those who had never smoked, men who smoked less than 20 cigarettes a day had a 1.7 times higher risk of hemorrhagic stroke and in men who smoked more than this, the risk went up to 2.4 times. Former smokers had about the same risk of hemorrhagic stroke as men who had never smoked. Previous research has also established that almost 12 per cent of all strokes are hemorrhagic strokes, caused by bursting of a blood vessel and bleeding into the brain and around 37 per cent of these strokes are fatal within 30 days.