Table 2.

FE_NO (ppb) of respiratory healthy subjects (n = 3378) according to smoking habits

Smoking groups	Women (n = 1741)				Men (n = 1637)
	n	Median	5th perc.	95th perc.	n	Median	5th perc.	95th perc.	p valuea
Never smokers	868	15.7	7.8	35.7	817	19.0	9.0	44.2	<0.0001
Former smokers	581	16.3	7.6	35.6	615	18.9	9.2	39.9	<0.0001
Current smokers	292	10.4b	4.4	29.4	205	13.2 b	6.2	34.3	<0.0001
All subjects	1741	15.0	6.6	35.3	1637	18.2	8.2	41.3	<0.001.

^a p values refer to differences between median values of FE_NO according to the Mann-Whitney

two sided test

^bdenotes a significant difference from the other smoking categories ANOVA)

Number of subjects, median values and the 5th and 95th percentiles of FE_NO (ppb) are presented