Ethnic and gender differences in cough reflex sensitivity

Background: Although recent studies have suggested that the cough reflex is more sensitive in women than in men, ethnic differences in cough reflex sensitivity have not previously been investigated. Objectives: To evaluate ethnic and gender differences in cough reflex sensitivity. Methods: We performed capsaicin cough challenge testing in 182 healthy volunteers of three distinct ethnic groups: Caucasian (white, non-Hispanic, of European origin), Indian (originating from the Indian subcontinent) and Chinese. The concentration of capsaicin inducing 2 or more (C-2) and 5 or more coughs (C-5) was determined in each subject. Results: Mean (+/- SEM) values for log C5 demonstrated that, within each ethnic group, the cough reflex was more sensitive in women: p = 0.00002 for Caucasian subjects; p = 0.003 for Indian volunteers; and p = 0.002 for Chinese subjects. Examination Of C-2 data yielded similar results. When subjects were evaluated by gender, multivariate analysis of variance demonstrated no ethnic differences in sensitivity to capsaicin. Conclusion: Our data do not support the presence of significant ethnic differences in cough reflex sensitivity, but do confirm previous data demonstrating lower cough thresholds in women. Copyright (C) 2001 S. Karger AG, Basel.