Asthma increases risk of lung damage

People with asthma are 12 times as likely to develop chronic obstructive pulmonary disease as those who do not have asthma, according to a new study.

People with asthma are 12 times as likely to develop chronic obstructive pulmonary disease as those who do not have asthma, according to a new study.While the two respiratory diseases share symptoms, they have always been considered distinct. But new research suggests that asthma and COPD “may share a common background” and asthma may lay the groundwork for the far more serious condition, said Graciela Silva, a researcher at the Respiratory Centre of the University of Arizona in Tucson.She said factors such as smoking and pollution may facilitate the evolution of asthma into COPD, and that means asthmatics should be particularly careful about their exposure to tobacco smoke and pollutants.COPD is the name of a group of chronic lung diseases, including severe forms of emphysema and chronic bronchitis. It is characterized by severe breathing problems and permanent lung damage. Asthma is not believed to cause permanent lung damage, and symptoms dissipate spontaneously or with medication.The findings, published in the medical journal Chest, are the result of a two-decade study of more than 3,000 Arizona residents.At the outset, participants were assessed for asthma, allergies and smoking status. Almost 200 had asthma, but none had COPD.After 20 years, the participants with asthma were far more likely to have developed more serious conditions: They were 10 times more likely to have bronchitis; 17 times more likely to have emphysema; and 12 times more likely to have COPD. (Patients can have bronchitis or emphysema without it having progressed to COPD.)Notably, the research did not find an association between childhood asthma and COPD later in life. Dr. Silva said this suggests that actively treating asthma may reduce the risk of COPD. But she stressed that more research is needed to determine how asthma progresses to COPD.Smoking is one clearly established risk factor. Virtually everyone who develops COPD is a smoker. That proved to be true in the study, though researchers noted that less than 20 per cent of smokers developed chronic obstructive lung disease.”Although most people living with COPD have a history of smoking, the majority of smokers do not develop COPD later in life, suggesting that other factors, such as genetic, occupational or environmental conditions convey significant risk,” Dr. Silva said.Research published in June in the medical journal Clinics of Chest Medicine shows that women are far more susceptible to COPD than men.What that means, practically speaking, is that women suffer far more lung damage than men do smoking the same number of cigarettes, said Kenneth Chapman, a physician at the Asthma and Airway Centre at Toronto Western Hospital.He said this is likely due to the fact that women have smaller airways as COPD is essentially a permanent narrowing of the breathing tubes.COPD is the fifth leading cause of death in Canada, and the only disease in the top five whose prevalence is increasing.Canadian data show that 3.6 per cent of women 35 or older suffer from COPD, compared with 2.8 per cent of men.Worldwide, more than three million people die annually of COPD. (Source: Globe and Mail Health, July 2004)