Smoking: it promotes the development of asthma in adolescence

Teens who smoke regularly have an increased risk of developing asthma, a U.S. study confirms.

Many studies have examined the role of in utero exposure to maternal smoking in the development of asthma or passive smoking during childhood but they are few to have examined the role of active smoking during adolescence, remember Frank Gilliland and his colleagues at the Keck School of Medicine in Los Angeles in the American Journal of Respiratory and Critical Care Medicine (AJRCCM).

Whether smoking may influence the risk of asthma in adolescence, the researchers conducted a prospective study of 2609 children, aged 8-15 years, with no history of asthma or wheezing at the time of inclusion in CM1 and 5th.

CM1 children were followed for 6.3 to 8 years, depending on the classes, and those of the fifth, for 4.1 to 5 years.

On the follow-up period, approximately 28% of children said they had never smoked, while 6.9% were considered regular smokers, that is to say at least seven cigarettes on average a week or more than 300 cigarettes in the year before each annual maintenance.

A total of 225 new cases of asthma diagnosed by a physician were reported, with an overall annual incidence of 17.8 cases per 100,000 person-years (19.4 for women and 16 for men).

The adjusted analysis of the data indicates that children reporting smoking more than 300 cigarettes per year are at risk of developing asthma almost quadrupled compared with nonsmokers. Those who smoked less does not seem to have a greater risk of asthma.

It also appears that allergic children who reported having smoked more than seven cigarettes a week before the annual maintenance had a fivefold risk of asthma compared with nonsmokers not allergic.

The risk of developing asthma in adolescence was higher among regular smokers who were exposed to maternal smoking in utero or during childhood, multiplied by 8.8 and 9.9 respectively, compared to non-smokers not exposed . But those who smoke regularly while having been exposed to secondhand smoke both in utero and during childhood had a lower risk of asthma, multiplied by 6.9.

These results confirm other evidence that regular smoking is a major risk factor for onset of asthma in childhood and adolescence, which emphasizes the importance of prevention campaigns targeting this population, conclude researchers.