Table 3

Prevalence of exhaled nitric oxide levels stratified by gender, race, age groups, smoking status, peripheral eosinophil count and clinical status

Demographic variable	Intermediate level FeNO group (FeNO=25–50 ppb) (N=445 085)			High level FeNO group (FeNO ≥51 ppb) (N=89 623)
Demographic variable	COPD without asthma history	COPD with asthma history	P value	COPD without asthma history	COPD with asthma history	P value
Total	13.0%(13.0% to 13.1%)	22.0%(21.9% to 22.2%)	<0.001	2.2%(2.2% to 2.3%)	6.7%(6.6% to 6.7%)	<0.001
Gender (95% CI)
Male	16.2%(16.2% to 16.3%)	13.6%(13.5% to 13.8%)	<0.001	2.0%(2.0% to 2.0%)	1.8%(1.7% to 1.8%)	<0.001
Female	6.1%(6.0% to 6.1%)	28.0%(27.9% to 28.2%)	<0.001	2.8%(2.7% to 2.8%)	10.2%(10.0% to 10.3%)	<0.001
Race (95% CI)
Non-Hispanic white	12.5%(12.4% to 12.5%)	9.0%(8.9% to 9.1%)	<0.001	2.2%(2.2% to 2.2%)	7.6%(7.5% to 7.7%)	<0.001
Non-Hispanic black	14.4%(14.2% to 14.6%)	57.9%(57.3% to 58.4%)	<0.001	0%	0%	NA
Hispanic	23.0%(22.7% to 23.3%)	0%	NA	11.5%(11.2% to 11.7%)	17.4%(16.9% to 18.0%)	<0.001
Other race	14.9% (14.7% to 15.1%)	100%(99.9% to 100.0%)	<0.001	0%	0%	NA
Age groups (95% CI)
40–49 years	20.9%(20.8% to 21.0%)	0%	NA	2.2%(2.2% to 2.3%)	0%	NA
50–59 years	5.0%(4.9% to 5.1%)	50.4%(50.1% to 50.7%)	<0.001	0%	0%	NA
60–69 years	9.7%(9.7% to 9.8%)	18.2%(18.1% to 18.4%)	<0.001	0%	11.6%(11.5% to 11.8%)	NA
70–79 years	32.9%(32.8% to 33.1%)	0%	NA	0%	0%	NA
Smoking status (95% CI)
Current smoker	2%(1.9% to 2.0%)	0%	NA	0%	0%	NA
Non-smoker	14.9%(14.8% to 14.9%)	35.3%(35.1% to 35.6%)	<0.001	4.8%(4.7% to 4.8%)	2.5%(23.9% to 25.6%)	<0.001
Unknown smoking status	21.5%(21.4% to 21.6%)	18.9%(18.7% to 19.0%)	<0.001	1.0%(1.0% to 1.1%)	9.6%(9.5% to 9.7%)	<0.001
Eosinophil count (cells/µL) (95% CI)
300andabove	11.1%(11.1% to 11.2%)	48.5% (48.3% to 48.8%)	<0.001	6.3%(6.2% to 6.3%)	0%	NA
299and below	14.0% (14.0% to 14.1%)	5.6%(5.5% to 5.6%)	<0.001	0%	10.8% (10.7% to 10.9%)	NA

NA, not available.