Table 1.

Participants’ characteristics by sex^a

	Males	Females	Total	p value*
	(N = 5062)	(N = 4396)	(N = 9518)
	%/mean (SD)	%/mean (SD)	%/mean (SD)
School grade
Secondary 1	24.71	23.23	23.98	0.043
Secondary 2	24.71	24.25	24.51
Secondary 3	26.49	26.00	26.31
Secondary 4	24.08	26.52	25.20
Father’s education level
Junior secondary school or below	26.51	29.50	27.83	<0.001
Senior secondary school or matriculation	37.34	39.04	38.22
University or college or above	18.25	14.70	16.57
Missing	17.90	16.77	17.38
Mother’s education level
Junior secondary school or below	27.12	30.48	28.66	<0.001
Senior secondary school or matriculation	40.34	43.06	41.67
University or college or above	15.27	11.03	13.25
Missing	17.27	15.42	16.42
Living arrangement with parents
Living with both parents	82.83	82.50	82.70	0.143
Living with the mother only	9.25	9.92	9.55
Living with the father only	3.14	2.82	2.99
Living with none of the parents	2.67	3.34	2.97
Missing	2.11	1.39	1.79
Father’s age (mean ± SD)	46.95 ± 6.78	47.08 ± 6.59	47.02 ± 6.68	0.428
Whether born in HK/length of residency
Yes, born in HK	79.89	77.05	78.58	<0.001
No, stayed in HK ≥7 years	11.81	13.33	12.53
No, stayed in HK <7 years	5.55	7.48	6.43
No, can’t remember when came to HK	2.00	1.66	1.84
Missing	0.75	0.48	0.62
HBM constructs
Perceived Susceptibility to IA	2.36 ± 1.08	2.35 ± 1.00	2.36 ± 1.04	0.558
Perceived Severity of IA	3.29 ± 1.26	3.52 ± 1.12	3.40 ± 1.20	<0.001
Perceived Barriers (reducing use)	10.39 ± 3.99	10.81 ± 3.82	10.59 ± 3.92	<0.001
Perceived Social Benefits (Internet use)	13.70 ± 4.20	13.40 ± 3.99	13.57 ± 4.11	<0.001
Cue to Action Scale (reducing use)	5.46 ± 2.05	4.91 ± 1.95	5.21 ± 2.03	<0.001
Perceived Self-efficacy (reducing use)	7.08 ± 2.04	7.30 ± 1.90	7.18 ± 1.98	<0.001
Perceived number of peers with IA (PNPIA)
Nil	16.69	18.08	17.35	<0.001
Only a few	41.21	52.30	46.34
Quite a number	29.26	24.57	27.10
A large number	12.84	5.05	9.21

Cases with missing information for gender were excluded from analysis (n = 60)

*χ² test or 2-sample t-test

^aFigures for the variable on school attended by participants (18 schools) were not listed in this table