The findings could help doctors better understand who is at risk of developing heart disease, the researchers said.
A blood type (also called a blood group) is a classification of blood based on the presence and absence of antibodies and also based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs).
These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system.
The new research analysed studies involving 1.3 million people and found that 15 in 1,000 people with a non-O blood group suffered a heart attack, compared to 14 in 1,000 people with blood group O.
Although the increase in risk was small, when applied to a whole population the numbers become more important. Previous research found that people with the rarest blood group – AB – were the most vulnerable, being 23 per cent more likely to suffer heart disease.
There are a number of factors which can increase the risk of heart disease, such as smoking, being overweight and leading an unhealthy lifestyle.
Which group an individual belongs to is determined by the genes inherited from both parents. Study author, Tessa Kole, from the University Medical Centre Groningen in the Netherlands, said more research was needed to work out the cause of the increased cardiovascular, CDV, risk in people with a non-O blood group. She stated that looking at the risk for each individual blood group would help.
She said: “In future, blood group should be considered in risk assessment for CDV prevention, together with cholesterol, age, sex and systolic blood pressure.”
People with blood group A – who are known to have higher cholesterol – may need a lower treatment threshold for high blood pressure, for example.
The analysis looked at coronary events in more than 770,000 people with a non-O blood group and more than 510,000 people with an O blood group.
Around 1.5 per cent in the first group and 1.4 per cent in the second experienced a heart attack or angina.
They also looked at CDV events in 708,000 people with non-O blood and 476,000 with O blood, which affected 2.5 per cent and 2.3 per cent of each group respectively.
When the researchers looked at fatal heart events, they found no major difference in risk between the O and non-O blood groups.
