Table 1.

Baseline characteristics of the case and control groups

	Case group	Control group	p value
Number [n (%)]	50 (42.7)	67 (57.3)	-
Age (year)	26.9± 4.9	26.0± 4.7	NS
CPD	13.4± 10.9	0	< 0.05a

*NS: non-significant; CPD: Cigarettes per day;

^a Significant difference between groups (p < 0.05)