Table 1.

The sociodemographic characteristics of the study population

Characteristics		N	%
Sex	Male	17,812	60.9
	Female	11,434	39.1
Age (years)	15–29	5,101	17.4
	30–49	17,272	59.1
	≥50	6,873	23.5
Smoking	Never	15,639	53.5
	Quit	3,230	11.0
	Current	10,377	35.5
Drinking	No	6,184	21.1
	≤1/week	15,050	51.5
	≥2/week	8,012	27.4
Education	Below Middle School	2,750	9.4
	High School	10,193	34.9
	College and beyond	16,304	55.7
Income (10,000won/month)	<100	2,339	8.0
	100–199	10,909	37.3
	200–299	9,113	31.2
	≥300	6,880	23.5
Job type	Professional	2,541	8.7
	Office	9,467	32.4
	Service	7,426	25.4
	Manual	9,813	33.6
Employment contract	Full time	27,683	94.7
	Part time	1,563	5.3
Work schedule	Nonshift	26,448	90.4
	Shift	2,799	9.6
Working hours/week	<35	1,557	5.3
	35–45	11,133	38.1
	≥45	16,557	56.6