Having blood type O almost trebles the risk of dying from serious injury because it does not clot as well, scientists have found.

Data from 901 emergency care patients in Japan showed a death rate of 28 per cent for those with type O blood.

The death rate of patients from other blood groups combined was 11 per cent.

Lead researcher Dr Wataru Takayama, from Tokyo Medical and Dental University Hospital, said: "Recent studies suggest that blood type O could be a potential risk factor for haemorrhage.

"Loss of blood is the leading cause of death in patients with severe trauma but studies on the association between different blood types and the risk of trauma death have been scarce.

"We wanted to test the hypothesis that trauma survival is affected by differences in blood types."