Young adolescents who take up smoking run the risk of developing wheezing and asthma while still in their teens, new research confirms.

In a study of nearly 3,000 German children followed for seven years, researchers found that those who took up smoking were more likely to develop wheezing problems or be diagnosed with asthma.

By the end of the study, one-third of the children were smoking, having started at age 14, on average. These teens were twice as likely as non-smokers to have developed symptoms of wheezing, and 2.5 times as likely to have been diagnosed with asthma, according to a report in the medical journal Thorax.

There have been few studies of the relationship between smoking and subsequent asthma development in teenagers, Dr. Stephan Weiland of the University of Ulm, a co-author of the new study, told Reuters Health.

He said these latest findings “add strong evidence” that smoking is a risk factor for asthma in adolescence.

The results are based on questionnaires and clinical exams of 2,936 children who were followed from the age of 10 through 17.

Those who started smoking during the study period were at greater risk of respiratory problems, with the risk climbing the longer or more heavily a teenager smoked.

Weiland said the findings offer teenagers further incentive to never take up smoking. Unlike other serious consequences of the habit - like heart disease, lung cancer and emphysema - asthma does not take years to show up.

Teenagers in this study, Weiland noted, had typically been smoking for less than three years.

SOURCE: Thorax, July 2006.