People who develop asthma as adults may be at greater risk of suffering heart disease or a stroke, scientists warn.
Those diagnosed after they turn 18 were 57 per cent more likely to suffer a cardiovascular event than those without the condition, experts discovered.
But patients diagnosed as children had the same risk of having heart failure as those without asthma, a study found.
And scientists revealed obese females are most at risk from being told they have asthma as they grow older.
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Those with late-onset asthma – defined as being 18 or older when diagnosed – were 57 per cent more likely to suffer a stroke than those without the condition
Experts believe the body’s immune response in asthma may raise the risk of hardening of the arteries.
Researchers from the University of Wisconsin followed 1,269 adults without cardiovascular disease over a period of 14 years.
The average age of asthma diagnosis in the late-onset group was 39.5 compared to just under nine years old in the early-onset group.
During the study period, researchers tracked cardiovascular events – including heart attack, stroke, heart failure and angina.
Lead researcher Dr Matthew Tattersall, said: ‘Though it’s usually not recognised as such, there are several different types of asthma, each with some unique features.
‘We looked at the type known as late-onset asthma, which tends to be more severe and more difficult to control with medicines than asthma that begins in childhood.’
People with late onset asthma compared to non-asthmatics were more likely to be female and to have a higher body-mass index.
The researchers speculated that a number of differences between early-onset and late-onset asthma may help explain the findings.
Experts believe the findings suggests doctors should pay more attention to heart disease risk factors in patients with late-onset asthma
They said, in addition to being harder to control, late-onset asthma is often triggered by different factors including air pollution and often leads to a more rapid decline in lung function.
Other studies have found an association between both air pollution and compromised lung function and cardiovascular disease.
Dr Tattersall believes that the study results suggests doctors should pay particular attention to heart disease risk factors in patients with late-onset asthma.
He said: ‘Doctors should be monitoring for high blood pressure and cholesterol closely in these patients and be aggressive in modifying any risk factors.’
He added that people with late-onset asthma can increase their chances of remaining heart healthy and stroke free by exercising, eating a healthy diet and maintaining a normal body weight.
The findings were published in the Journal of the American Heart Association.
Previous research found a clear link between the onset of asthma in adulthood and heart and circulatory health.
Women diagnosed with the condition as adults are twice as likely to have heart disease than men, a study of 15,000 people discovered.
The increased risks was found to not apply to men, nor to the more common form of asthma, which develops during childhood.
Experts said it was unclear why the link applied to women and not to men, but believed the female sex hormone oestrogen may play a role.