Children who smoke higher asthma risk

Children who smoke are almost four times more likely to develop asthma than those who don't smoke, and their risk is even greater if their mothers smoked while pregnant with them, a new study shows.

The increased risk of developing an activity-limiting chronic disease, such as asthma, after becoming a regular smoker "may provide new motivation for adolescents to refrain from smoking," Dr. Frank D. Gilliland of the University of Southern California in Los Angeles and colleagues state.

While a mother's exposure to second-hand smoke during pregnancy has been tied to greater childhood asthma risk, along with being exposed to second-hand smoke in childhood, the effect of a child or teen's own smoking on asthma development is less clear, Gilliland and his team write.

To investigate, they followed 2,609 fourth- and seventh-graders in 12 southern California communities through their graduation from high school. Researchers interviewed the study participants annually and classified them according to smoking status.

During follow-up, 28 per cent of the children reported any smoking at all, while 13.8 per cent smoked weekly and 6.9 per cent smoked daily (regular smokers).

Children who said they smoked seven cigarettes a week in the previous year had a 3.1-times greater risk of developing asthma during the course of the study, while those who had smoked at least 300 cigarettes in the past year were at 3.9-fold increased risk.

Meanwhile, researchers say that a new clinical tool to help doctors identify asthma patients most likely to need hospital treatment could improve the care of patients and reduce costs.

In a three-year study published in the European Respiratory Journal, patients with the highest score were 10 times more likely to need emergency treatment or be admitted to hospital than other asthma sufferers