Differences between the patients and comparison subjects were assessed through multivariate analyses of variance, with diagnosis and race as between-subject factors, nostril (left/right) as a within-subjects factor, and height and smoking status (pack-years) as covariates. For nasal volume, compartment (anterior/posterior) was an additional factor. There were no significant main or interaction effects of diagnosis on airflow resistance, minimum cross-sectional area, or location of the minimum cross-section. There was a significant main effect of diagnosis on nasal volume (lower in patients than comparison subjects) (F=7.96, df=1, 58, p<0.01) but no effect of race (F=3.12, df=1, 58, p=0.08) and no interaction between diagnosis and race (F=0.18, df=1, 58, p=0.68). There was a significant interaction between diagnosis and nasal compartment (F=9.72, df=1, 58, p<0.01). Post hoc contrasts indicated that the patients had smaller posterior nasal volumes than the comparison subjects (F=10.64, df=1, 58, p<0.01) but did not differ in anterior nasal volume (F=2.64, df=1, 58, p=0.11). The difference in posterior volume was present for both the left (F=8.10, df=1, 58, p<0.01) and right (F=7.31, df=1, 58, p<0.01) nostrils. Mean group volumes for each compartment by nostril are presented in F2. On a percentage basis, the posterior nasal volume was 31% smaller in the patients, compared to an 11% smaller anterior volume.