Table 1.

Demographics of the participants.

	Smokers	Non-smokers
Number	100	100
Age	31.9 ± 9.5	32.6 ± 9.9
Gender	53 M, 47 F	53 M, 47 F
FTND	5.3 ± 1.9	–
CPD	18.2 ± 6.8	–
Smoking years	15.3 ± 9.4	–
Lifetime usage	14.5 ± 11.9	–

P > 0.6 on age between smokers and non-smokers.

FTND: Fagerström Test for Nicotine Dependence.

CPD: cigarettes per day.

Lifetime usage: measured in pack-years (= CPD × smoking years/20).

M/F: male/female.

Age, FTND, CPD, smoking years and lifetime usage are calculated in mean ± SD.