The long-held belief that asthma is caused by "twitchy" airway passages in the lungs is inaccurate, reseachers at the University of British Columbia's Pulmonary Research Laboratory say.
The real cause is a thickening of airway walls that sometimes expand two or three times their normal size, says Dr. Tony Bai. The thickening is especially pronounced in those who suffer fatal asthma attacks. Bai said the thickening was found in 45 asthmatics who were autopsied or had part of a lung removed."When the airways are thick, they close off very easily," Bai reported. "That means you don't need abnormal muscle constriction to trigger an asthma attack."