People with type A, B, or AB blood have a greater chance of suffering a heart attack or chest pain during episodes of high air pollution compared to those with type O, scientists have found.
Researchers warned that people in those groups should consider staying indoors to minimise their risk if they had underlying heart conditions, such as coronary artery disease.
Scientists have known for some time that pollution raises the chance of a heart attack but it is the first time that the risk has also been linked to blood type.
A study of 14 years of patient data from the Intermountain Medical Center Heart Institute in Utah, US, found that the risk of a heart attack or chest pain doubled for people of type A, B, or AB blood when pollution hits high levels.
In contrast the risk rose only rose by 40 per cent for those with type O.
“The association between heart attacks and pollution in patients with non-O blood isn’t something to panic over, but it is something to be aware of,” said Dr Benjamin Horne, a clinical epidemiologist and lead investigator of the study from the Intermountain Medical Center Heart Institute in Salt Lake City.
“In the information we provide to our patients about pollution, we try to stress that they can do something about it to reduce their risks: Stay indoors out of pollution. Exercise indoors.”
Air pollution in Britain is thought to contribute to around 40,000 early deaths a year, according to the Royal Colleges of Physicians and of Paediatrics and Child Health.
The study found that for every additional 10 micrograms over 20, the risk to people with type A, B, or AB blood increased by 25 per cent, but only by 10 per cent for people with type O.
Around 55 per cent of people are A, B, or AB and they are thought to be at greater risk of heart problems because their blood contains greater quantities of a clotting agent.