Table 1

Characteristics of the study population

Characteristic	Exposed		Reference		Total		p value
Characteristic	n	%	n	%	n	%	p value
*BMI, body mass index. Values shown are mean (SD).
Comparison between the exposed and reference groups.
Number of subjects	47	63.5	27	36.5	74	100
Age
18–24	24	51.1	7	25.9	31	41.9	0.04
25–29	10	21.3	13	48.2	23	31.1
30–	13	27.6	7	25.9	20	27.0
Marital status
Married	3	6.4	8	29.6	11	14.9	0.007
Single	44	93.6	19	70.3	63	85.1
Education
High school	30	63.8	26	96.3	56	75.7	0.002
College	17	36.2	1	3.7	18	24.3
Current smoking habits
Smokers	5	10.6	8	29.6	13	17.6	0.03
Non-smokers	42	89.4	19	70.4	61	82.4
Transportation
Motorcyclist	6	12.8	16	59.3	22	29.7	<0.001
Others	41	87.2	11	40.7	52	70.3
Daily use of incense
Yes	8	17.0	16	59.3	24	32.4	<0.001
No	39	83.0	11	40.7	50	67.6
BMI (kg/m²)*	21.23 (3.22)		21.32 (4.07)		21.26 (3.52)		0.47