An interaction between Nrf2 polymorphisms and smoking status affects annual decline in FEV1: a longitudinal retrospective cohort study

Table 1 Characteristics of the participants^a

Characteristic	Participants (N = 915)
Age (years)	52.1 ± 8.3
Male sex - N (%)	418 (45.7)
Total duration of follow-up (years)	11.1 ± 4.6
Number of visits	9.1 ± 3.7
BMI	23.1 ± 3.0
FVC (L)	3.12 ± 0.78
FVC % predicted (%)	100.5 ± 13.6
FEV₁ (L)	2.56 ± 0.64
FEV₁/FVC (%)	82.2 ± 5.6
FEV₁ decline (mL/year)	23.8 ± 26.3
Serum IgE (Log IU/mL)	1.78 ± 0.59
Smoking habits - N (%)
Never-smokers	576 (63.0)
Ex-smokers	210 (23.0)
Current-smokers	129 (14.1)
Smoking index^b - N (%)
0	576 (63.0)
0-200	114 (12.5)
> 200	225 (24.6)
Asthma - N (%)	47 (5.1)

^a Data are presented as mean ± SD or n (%).
^b Smoking index was calculated for current and past smokers by multiplying smoking dose (cigarettes per day) and duration (years smoked).

ISSN: 1471-2350