Inhalers that give short-term relief from asthma can increase the risk of attacks if the drug is given regularly, a new study has shown.

Scientists analysed fluctuations in twice-daily measurements of airway obstruction in 80 asthma patients for 18 months to reach their conclusion. They managed to use the state of the airways to calculate the chances of severe asthma attacks within the next month.

In the latest issue of Nature, Prof. Urs Frey, of the University Children’s Hospital of Berne, Prof. Bela Suki, of Boston University, and colleagues report that one type of asthma medication ? called a short-acting beta-agonist bronchodilator, such as salbutamol ? increased future risk, while another type ? a long-acting bronchodilator, based on formoterol ? decreased it.

Frey stressed that the short-acting drug was still very useful and the first-line drug for treating acute attacks.

But when given four times each day for long periods, as some doctors recommend to prevent attacks, the short-term treatment made the airways function more random and variable than the long-term treatment.

“Long-acting bronchodilators are more effective at stabilising airway function over extended periods,” the team said in Nature.

Asthma affects millions of people around the world, including one in 10 children and one in 12 adults. Many aspects of modern lifestyles, such as changes in housing and diet and a more hygienic environment, may have contributed to the rise in asthma over the last few decades. Environmental pollution can aggravate symptoms but has not been proven to cause the condition.

The Daily Telegraph