THE same gene that causes people to be blood group 'O gives them some protection against heart attacks, a study published Saturday online in The Lancet has found. Almost half the British population has the blood type, making it the most common group. American scientists have found that the same gene that creates the enzyme which makes people 'O offers them some protection against heart attacks. The researchers compared almost 6,000 people who had suffered a heart attack with 7,400 people who had a type of coronary heart disease, but had not had a heart attack. They described the association as notable, in view of decades of work suggesting a relation between ABO blood-groups and both thrombosis and coronary heart disease. Telegraph