Sex differences in pulmonary function parameters among Indigenous Australians with and without chronic airway disease

Background Studies assessing normative values and sex differences in pulmonary function test parameters (PFTPs) among Indigenous populations are sparse. Methods PFTPs were compared between male and female Indigenous Australian adults with and without chest radiologically proven chronic airway diseases (CADs). Results 485 adults (56% were female) with no significant difference in age, body mass index or smoking status between sexes were included. Females displayed a higher prevalence of radiology without CADs compared to males (66 vs. 52%, respectively). Among patients without CADs, after adjustment for age, stature and smoking, males displayed significantly higher absolute values of Forced Vital Capacity (FVC) (mean difference, 0.41L (0.21,0.62), p<0.001) and Forced Expiratory Volume in one second (FEV₁) (mean difference 0.27L (0.07,0.47), p<0.001), with no significant difference in FEV₁/FVC ratio (mean difference -0.02 (-0.06, 0.02), p = 0.174). Male and female patients with radiologically proven CADs demonstrated lower FEV₁/FVC values. However, compared to females, males showed significantly greater reductions in pre- [-0.53 (-0.74, -0.32) vs. -0.29 (-0.42, -0.16), p = 0.045] and post- [-0.51 (-0.72, -0.3) vs. -0.27 (-0.39, -0.14), p = 0.049] bronchodilator FEV₁