Asthma in Adults More Than Doubles Over Two Decades
July 7, 2000 -- A large study in Scotland confirms what physicians and researchers have been saying for some time: the number of asthma sufferers worldwide is growing at a rapid clip.
Asthma is a chronic inflammatory lung disease characterized by episodes of breathlessness, wheezing, coughing, and chest tightness, which can range from mild to life-threatening. Among the things that can trigger these episodes are respiratory infections, exercise, or stress, or exposure to allergens such as dust mites, cockroaches, animal dander, mold, smoke, and other pollutants. Previous studies have shown that asthma has been increasing in children during the past few decades, but there has been little information about adults, the Scottish researchers say.
The researchers, based on a study of married couples living in the towns of Renfrow and Paisley in 1972 and 1975, and of their offspring 20 years later, found that the level of asthma -- and hay fever -- in adults had more than doubled in those two decades. Nearly 4,000 people took part in the study.
"Our findings mirror the increase health organizations have been reporting worldwide," researcher Mark Upton, MD, tells WebMD. Upton is a general practitioner and clinical epidemiologist at the Thornaby and Barwick Medical Group in Cleveland, U.K.
Hay fever is considered a risk factor in developing asthma, and the authors of the Scottish study found that both hay fever and asthma increased during the 20-year interval, in both smokers and nonsmokers. In people who had never smoked, the incidence of hay fever rose from 6% to 20%, and asthma from 3% to 8%. In those who had smoked, hay fever rose from 5% to 16%, and asthma from 2% to 5%. The percentage of study participants who smoked declined by half during the 20-year period, according to the study, which was published in the British Medical Journal.
Despite the increase in asthma, the researchers found that reports of frequent chest wheezing decreased over time. In addition to the fact that fewer of the younger study participants smoked, Upton says the reduced wheezing might be the result of better asthma treatments. In the U.S., other experts say, prescriptions of inhaled steroid medications for asthma increased more than sixfold from 1980 to 1990.