Background:Sex difference in quality of life and association between cough and quality of life for subacute cough remains unknown.This study aimed to investigate whether health related quality of life is different by sex,and whether association between cough and quality of life is modified by sex.Methods:Secondary analysis was performed on 180 participants with postinfectious cough in a multisite randomized controlled trial(recruitment from April 2011 to March 2012).Baseline demographics,clinical characteristics and cough specific quality of life questionnaire(CQLQ)were collected.Linear regression analyses were used to examine sex difference in CQLQ and association between cough and CQLQ in postinfectious cough.Results:In the unadjusted analysis,difference between women and men was not significant in total CQLQ(65.4 versus 63.3,P = 0.077),and was marginally significantly in association between cough severity and total CQLQ(2.40-point versus 0.73-point,P = 0.053).After adjusting for age,cough duration,cough severity,and clinical center,total CQLQ score was 2.20-point higher in women versus men(0.11 to 4.30,P= 0.039);an increase of 1-point in cough severity was associated with a 2.55-point(1.16 to 3.95)increase in total CQLQ in women versus a 1.26-point(0.20 to 2.31)increase in men(P = 0.020).Conclusions:Women are associated with worse CQLQ than men in postinfectious cough;womens CQLQ are more significantly impaired as cough severity increases.