Table 1. Characteristics of the analytical participants for secondhand smoke at home (n = 1,738).

	Total	Second hand smoke at home
		None		Once a week or less		Several times a week		Almost everyday		Missing		P-valuea
	n	n	%	n	%	n	%	n	%	n	%
Age, years
20–39	350	238	68.0	25	7.1	21	6.0	51	14.6	15	4.3	<0.001
40–59	620	455	73.4	22	3.5	21	3.4	70	11.3	52	8.4
≥60	768	459	59.8	42	5.5	24	3.1	54	7.0	189	24.6
Sex
Men	682	496	72.7	29	4.3	12	1.8	20	2.9	125	18.3	<0.001
Women	1,056	656	62.1	60	5.7	54	5.1	155	14.7	131	12.4
Education, years
≤9	296	139	47.0	19	6.4	12	4.1	28	9.5	98	33.1	<0.001
10–12	806	519	64.4	44	5.5	31	3.8	99	12.3	113	14.0
≥13	627	492	78.5	26	4.1	23	3.7	47	7.5	39	6.2
Missing	9	2	22.2	0	0.0	0	0.0	1	11.1	6	66.7
Income
Low	700	418	59.7	44	6.3	30	4.3	85	12.1	123	17.6	<0.001
Middle	575	419	72.9	27	4.7	14	2.4	47	8.2	68	11.8
High	334	258	77.2	11	3.3	10	3.0	25	7.5	30	9.0
Missing	129	57	44.2	7	5.4	12	9.3	18	14.0	35	27.1
Smoking
Former smoker	515	356	69.1	22	4.3	16	3.1	30	5.8	91	17.7	<0.001
Never smoker	1,223	796	65.1	67	5.5	50	4.1	145	11.9	165	13.5
Total	1,738	1,152	66.3	89	5.1	66	3.8	175	10.1	256	14.7
	mean (SD)	mean (SD)		mean (SD)		mean (SD)		mean (SD)		mean (SD)		P-valueb
Number of people in householdc	3.3 (1.3)	3.2 (1.2)		3.6 (1.3)		3.5 (1.4)		3.6 (1.1)		2.9 (1.3)		<0.001
Knowledge of the adverse health effects of tobaccod	7.2 (3.4)	7.4 (3.3)		6.7 (3.4)		6.2 (3.9)		6.5 (3.5)		7.3 (3.6)		0.002

SD, standard deviation.

^aP-value from chi-squared test.

^bP-values from analyses of variance.

^cMissing information (n = 303) were excluded.

^dMissing information (n = 3) were excluded.