MedWire News: People with the hayfever-like condition rhinitis face an increased risk of developing asthma, but smoking may increase this risk even further, researchers have found.

"Rhinitis has been shown to be an important risk factor for the development of asthma," explain Dr Riccardo Polosa, from the University of Catania in Italy, and colleagues.

But they add that, until now, little was known about the effects of smoking on asthma risk in rhinitis patients.

Dr Polosa and team studied 325 rhinitis patients, aged between 18 and 40 years, who did not have asthma at the start of the study in 1990-1991.

All the participants were asked whether they were smokers and, if so, how many cigarettes they usually smoked.

The patients were then monitored for 10 years and all those who developed asthma during this time were identified.

The researchers found that smoking was significantly associated with asthma risk among the participants. Indeed, rhinitis patients who smoked were nearly three times more likely to develop asthma during the monitoring period than those who did not smoke.

Furthermore, patients who were heavy smokers were more likely to develop asthma than those who were light smokers, and patients who had smoked for many years were more likely to develop the respiratory condition than those who had started smoking more recently.

"Our results suggest that smoking is strongly predictive of the development of new-onset asthma in adults with allergic rhinitis," Dr Polosa and team write in the Journal of Allergy and Clinical Immunology.

They add: "Physicians have the responsibility to alert their patients with allergic rhinitis about the additional [asthma] risk they have if they smoked."