A third of adults diagnosed with asthma may not actually have the condition, research suggests.
Experts think many people are misdiagnosed with the condition, while others recover to the extent the asthma is no longer active.
They say doctors are too often diagnosing their patients with asthma without doing the proper tests.
‘Doctors wouldn’t diagnose diabetes without checking blood sugar levels, or a broken bone without ordering an X-ray,’ lead author Professor Shawn Aaron said last night.
‘But for some reason many doctors are not ordering the spirometry tests that can definitely diagnose asthma.’
The Canadian researchers carried out breathing tests on 613 patients who had been diagnosed with asthma in the last five years.
They found 33 per cent of patients showed no sign of asthma.
Yet eight in ten of these had been taking medication, 35 per cent of them every day.
More than 90 per cent of patients with no asthma were able to stop their medications and remained safely off treatment for a year of monitoring, the team found.
The study, led by the University of Ottowa, echoes research which suggests asthma is hugely over-diagnosed in the UK as well.