Table 1.

Socio-demographic characteristics of the participants according to their case-control status

	Case		Control		Overall		p-value#
n	%	n	%	n	%
Sex
Male	151	54.1	149	53.4	300	53.8	0.93
Female	128	45.9	130	46.6	258	46.2
Age, years (mean ± SD)	18.7±3.2		18.2±4.1		18.4±3.7		0.099
10–14	34	12.2	58	20.8	92	16.5
15–19	113	40.5	90	32.3	203	36.4
20–24	131	47.3	132	47.0	263	47.1
Occupation status
None	83	29.7	86	30.8	169	30.3	0.003
Student	90	32.3	84	30.1	174	31.2
Self-employed	45	16.1	72	25.8	117	21.0
Government employee	46	16.5	34	12.2	80	14.3
Unskilled worker	15	5.4	3	1.1	18	3.2
Physical exercise
No	221	79.2	178	63.8	399	71.5	<0.001
Occasionally	42	15.1	77	27.6	119	21.3
Regularly	16	5.7	24	8.6	40	7.2
On a diet
No	265	95.0	240	86.0	505	90.5	<0.001
Yes	14	5.0	39	14.0	53	9.5
BMI, kg/m2 (mean ± SD)	24.5±2.8		24.0±2.7		24.3±2.8		0.077
<18.5	4	1.4	0	0.0	4	0.7
18.5–23	89	31.9	104	37.3	193	34.6
>23	186	66.7	175	62.7	361	64.7
Smoking habits
No	242	86.7	233	83.5	475	85.1	0.34
Ex/current smoker	37	13.3	46	16.5	83	14.9
Cannabis habits
No	257	92.1	260	93.2	517	92.7	0.74
Ex/current user	22	7.9	19	6.8	41	7.3
Age at menarche, years (mean ± SD), (n=225)*	12.8±0.7		12.7±0.8		12.7±0.7		0.35
≤12	34	28.6	36	34.0	70	31.1
>12	85	71.4	70	66.0	155	68.9
Sibling history of acne, (n=516)**
No	135	51.7	204	80.0	339	65.7	<0.001
Yes	126	48.3	51	20.0	177	34.3
Sleep duration, hours (mean ± SD)	7.6±1.3		8.4±1.3		8.0±1.3		<0.001

Notes: ^#p-value for independent t-test and Pearson X² test were used to assess the differences between case and control groups. *Girls who had not reached menarche were excluded from analysis. **Subjects whose sibling history of acne was unknown were excluded from analysis.