Table 3.

Comparison (%) of sociodemographic, lifestyle, mental health-related factors between early conventional cigarette and electronic cigarette attempt (n=12428)

Factors	Variables	Categories	Early C-cig user	Early E-cig user	p*
			n=10171	n=1106
Sociodemographic factors	Sex	Male	89.7	10.3	0.004
		Female	91.6	8.4
	School year	7	83.3	16.7	<0.001
		8	85.3	14.7
		9	85.5	14.5
		10	90.2	9.8
		11	92.6	7.4
		12	93.3	6.7
	Residence	Province	90.0	10.0	0.565
		Metropolitan	90.6	9.5
		Other city	89.9	10.1
	Household income	Low-mid	91.4	8.6	<0.001
		Mid	90.8	9.2
		Mid-high	88.3	11.7
	Weekly allowance (thousand KRW)	<20	89.8	10.2	0.547
		20–40	90.4	9.6
		≥40	90.2	9.5
	Self-rated academic success	Low-mid	91.0	9.0	0.013
		Mid	90.0	10.0
		Mid-high	89.0	11.0
Mental health factors	Obesity (BMI >25 kg/m2)	No	90.8	9.2	0.868
		Yes	91.0	9.0
	Effort to reduce body weight	No	90.1	9.9	0.504
		Yes	90.5	9.5
	Subjective cognition of body shape	Not obese	89.8	10.2	0.055
		Obese	90.9	9.1
	Stress	High	91.0	9.0	0.011
		Mild	90.1	9.9
		Little	88.6	11.3
	Sadness	No	90.5	9.5	0.103
		Yes	89.5	10.5
	Subjective health	Good	89.5	10.5	0.001
		Moderate	92.0	8.0
		Bad	91.6	8.5
	Subjective happiness	Good	89.4	10.6	0.003
		Moderate	91.2	8.8
		Bad	90.2	9.8
Smoking-related environments	SHS exposure	No	91.8	8.2	<0.001
		Yes	87.8	12.2
	Presence of family members who smoked	No	90.5	9.5	0.381
		Yes	90.0	10.0
	Presence of friends who smoked	No	88.0	12.1	<0.001
		Yes	90.7	9.3
Behavioral & Lifestyle factors	Alcohol abuse (CRAFFT)	No	89.0	11.0	<0.001
		Yes	94.1	5.9
	Use of caffeine drink	No	90.8	9.2	<0.001
		Yes	87.1	12.9
	Weekday internet use for recreation	No	88.5	11.5	<0.001
		Yes	91.3	8.7
	Regular moderate-intensity physical activity (days/week)	<5	90.7	9.3	0.001
		≥5	88.3	11.7

C-cig: conventional cigarette. E-cig: electronic cigarette. Thousand KRW: 1000 Korean Won, about 0.834 US$. CRAFFT: Car, Relax, Alone, Forget, Friends, and Trouble. BMI: body mass index. SHS: secondhand smoke.

^*By chi-squared test.