Table 1. Characteristics of the participants in 2013.

Categorical variables	Male, No.	Proportion, %	Female, No.	Proportion, %
Social and demographic factors
Age	60,051	100.00	121,670	100.00
Younger (19-39 yr)	13,862	23.08	30,672	25.21
Middle-aged (40-59 yr)	21,270	35.42	46,006	37.81
Older (60 yr and older)	24,919	41.50	44,992	36.98
Education	59,982	100.00	121,522	100.00
≤ Elementary school	11,800	19.67	41,553	34.19
Middle school	7,746	12.91	13,231	10.89
High school	16,513	27.53	31,525	25.94
College or higher	23,923	39.88	35,213	28.98
Household income yearly	58,097	100.00	117,489	100.00
1st quartile (lowest)	13,833	23.81	32,220	27.42
2nd quartile	15,716	27.05	29,876	25.43
3rd quartile	15,079	25.95	29,679	25.26
4th quartile (highest)	13,469	23.18	25,714	21.89
Location of residence	60,051	100.00	121,670	100.00
Rural area	20,313	33.83	40,278	33.10
Urban area	39,738	66.17	81,392	66.90
Health-related factors
Smoking status	60,040	100.00	121,664	100.00
Never smoker	25,044	41.71	118,647	97.52
Ex-smoker	34,996	58.29	3,017	2.48
Drinking	60,045	100.00	121,656	100.00
No	16,307	27.16	53,566	44.03
Yes	43,738	72.84	68,090	55.97
Physical activity	60,042	100.00	121,644	100.00
No	41,105	68.46	99,814	82.05
Yes	18,937	31.54	21,830	17.95
Home-related factors
Housing type	60,051	100.00	121,670	100.00
Detached house	28,342	47.20	56,178	46.17
Apartment house	23,189	38.62	47,282	38.86
Row house	3,278	14.14	7,128	15.08
Multiplex house	3,837	16.55	8,401	17.77
Commercial building house	1,077	28.07	2,098	24.97
Others	328	8.55	583	6.94
Family type	60,051	100.00	121,668	100.00
Single-person household	3,915	6.52	16,355	13.44
Couple	20,935	34.86	29,920	24.59
The first generation or other sibling or relatives	750	1.25	1,663	1.37
Couple with unmarried children	23,863	39.74	45,642	37.51
Single father with unmarried children	916	1.53	554	0.46
Single mother with unmarried children	1,392	5.83	7,268	15.92
Couple with their parent(s)	1,482	2.47	3,483	2.86
Grandparent(s) with unmarried grandchildren	392	28.16	992	13.65
Couple with children and couple's brothers or sisters or other type of second-generation family	1,285	2.14	3,025	2.49
Three-generation family	5,121	8.53	12,766	10.49
Work-related factors
Employment	43,153	100.00	62,483	100.00
Employer and owner-operator	19,044	44.13	14,577	23.33
Paid worker	23,216	53.80	37,624	60.21
Unpaid family worker	893	2.07	10,282	16.46
Occupation	43,242	100.00	62,578	100.00
Officials or managers	7,670	17.74	11,137	17.80
Professionals	5,670	13.11	8,599	13.74
Service workers	2,317	5.36	9,107	14.55
Sale workers	3,040	7.03	7,053	11.27
Skilled agricultural or forestry or fishery	10,744	24.85	13,618	21.76
Craft and related trades workers, plant or machine operators assemblers	8,971	20.75	2,777	4.44
Manual laborer	4,402	10.18	10,264	16.40
Professional soldiers	428	0.99	23	0.04
SHS exposure
At home	60,049	100.00	121,659	100.00
No	57,685	96.06	107,318	88.21
Yes	2,364	3.94	14,341	11.79
In the workplace	42,170	100.00	59,739	100.00
No	31,992	75.86	49,995	83.69
Yes	10,178	24.14	9,744	16.31
In a public place	60,037	100.00	121,594	100.00
No	9,318	15.52	22,860	18.80
Yes	50,719	84.48	98,734	81.20

SHS, secondhand smoke.

^* P value < 0.05 in all variables by χ ² test.