Quitting smoking may have a quick payoff for people with asthma.
A single smoke-free week may be all it takes to start seeing improvements in asthma patients' lung function, researchers report in the American Journal of Respiratory and Critical Care Medicine.
"In smokers with asthma, improvement in lung function occurs as early as one week after smoking cessation, with a further improvement up to six weeks," write Rekha Chaudhuri, M.D., and colleagues. Chaudhuri works at Scotland's University of Glasgow.
"Active cigarette smoking is known to worsen the severity of asthma," the researchers point out. They studied 20 asthma patients (average age: mid- to late 40s) who were smokers.
The patients had smoked for at least 28 years and currently smoked more than 20 cigarettes a day, on average. For the study, half agreed to quit smoking for at least six weeks. The others kept on smoking.
Before and after the experiment, patients took lung function tests.
In one of those tests, the patients forcibly exhaled as much air as possible in one second's time. When the study started, the patients' scores on that test were lower than what would be expected for normal, healthy lungs.
After one week of not smoking, scores on that same lung function test — called FEV1 — began to improve. The gains continued for six weeks for the new nonsmokers.
The quit-smoking group also showed a drop in neutrophils — a type of white blood cell — in the thick fluid called sputum made in the lungs and airways. Neutrophils are part of the body's immune system, which helps fight off infection and illness. They can also be used as a measure of inflammation.
Meanwhile, no such improvements were seen in the patients who kept smoking.
"These findings highlight the importance of smoking cessation in asthma," the researchers conclude.
SOURCES:: Chaudhuri, R. American Journal of Respiratory and Critical Care Medicine, July 15, 2006; Vol. 174: pp. 127-133. WebMD Medical Reference from Healthwise: "Lung Function Tests." WebMD Medical Reference from Healthwise: "Sputum Culture." News release, American Thoracic Society.
By Miranda Hitti
Reviewed by Louise Chang M.D.
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