Table 1.

Characteristics of participants.

Variables	Category	N	%
Sex	Male	835	71.9
	Female	326	28.1
Age (years)	18–25	206	17.7
	26–30	297	25.6
	31–40	428	36.8
	41–50	191	16.5
	>50	39	3.4
Education level	≤Middle school	265	22.8
	High school	506	43.6
	College	241	20.8
	University	129	11.1
	≥Graduate school	20	1.7
Marital status	Unmarried	301	25.9
	Married	676	58.2
	Separated	104	9
	Widowed	61	5.3
	Divorced and others	19	1.6
Monthly income (¥)	<3,000	56	4.8
	3,000–4,999	363	31.3
	5,000–6,999	398	34.3
	7,000–9,000	214	18.4
	9,000–10,999	86	7.4
	≥11,000	44	3.8
Working age	0–5	564	48.6
	6–10	227	19.6
	11–15	172	14.8
	>15	198	17.0
Shiftwork status	No	758	65.3
	Yes	403	34.7
Drinking	No	414	35.7
	Yes	747	64.3
Smoking	No	488	42
	Yes	551	47.5
	Quit smoking	122	10.5
Regular exercise	No	622	53.6
	Yes	539	46.4
Working hours	≤40	122	10.5
	41–55	258	22.2
	56–70	376	32.4
	71–85	335	28.9
	≥86	70	6