Effect of smoking cessation on cough reflex sensitivity

¹ Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, USA
² Kaunas University of Medicine, Kaunas, Lithuania

^* To whom correspondence should be addressed. E-mail: pdicpinigaitis{at}pol.net.

	Abstract

Recent studies have shown that cigarette smokers have diminished cough reflex sensitivity compared to nonsmokers. We proposed a mechanism of chronic cigarette smoke-induced desensitization of airway cough receptors.

To r investigate this hypothesis, we measured cough sensitivity to inhaled capsaicin (C₅) in chronic smokers while they were actively smoking and 2, 6, 12 and 24 weeks after smoking cessation.

Twenty-nine subjects underwent baseline capsaicin challenge while smoking and two weeks after smoking cessation. Mean (±SEM) log C₅ fell from 1.86±0.12 to 1.60±0.12 (p=0.0004), demonstrating significant enhancement of cough reflex sensitivity. Twenty, 18, and 14 subjects successfully abstained from smoking for 6, 12 and 24 weeks, respectively. Mean log C₅ after 12 and 24 weeks of smoking cessation were significantly diminished from baseline (p=0.03 and p=0.008, respectively). In a control group of smokers, mean log C₅ did not decrease from baseline after 6, 12 and 24 weeks. Overall, the log C₅ profile of the smoking cessation group showed a clear, linearly-decreasing trend over time compared to the control group (p=0.0001).

Even after many years of smoking, cough sensitivity is enhanced as early as two weeks after smoking cessation. Given the importance of an intact cough reflex , these changes may provide clinical benefit.