Smoking habit and secretor status modify perception of methacholine-induced bronchoconstriction

The perceived dyspnea measured on a 10-cm visual analog scale per one percent decrease of FEV1 during bronchial challenge with methacholine was measured in a large group of travertine workers. The perceived dyspnea for FEV1 reductions up to 10-15% was lower in smokers , suggesting either a selection of less symptomatic workers among smokers and/or a smoke-related damage of sensitive nerves. Genetic factors seem also involved, as the ABO secretor status was a significant modifying variable of perceived dyspnea