Interaction of smoking and being bullied on suicidal behaviors: a school-based cross-sectional survey in China

Table 2 Association of smoking, being bullied, and suicidal behaviors in Chinese adolescents

Variable	Suicidal ideation (n=4892)				Suicidal plan (n=2493)				Suicidal attempt (n=983)
Variable	n (%)	Crude OR (95% CI)	Adjusted OR (95% CI)^a		n (%)	Crude OR (95% CI)	Adjusted OR (95% CI)^a		n (%)	Crude OR (95% CI)		Adjusted OR (95% CI)^a
Smoking
No	4671 (25.5)	Ref	Ref		2256 (12.3)	Ref	Ref		798 (4.4)	Ref		Ref
Yes	311 (53.7)	3.39 (2.87–4.00)^***	3.47 (2.91–4.12)^***		237 (40.9)	4.94 (4.16–5.86)^***	4.83 (4.03–5.78)^***		185 (32.0)	10.31 (8.54–12.45)^***		9.47 (7.74–11.59)^***
Being bullied
No	3304 (22.0)	Ref	Ref		1531 (10.2)	Ref	Ref		552 (3.7)		Ref	Ref
Yes	1678 (43.1)	2.69 (2.49–2.89)^***	2.74 (2.54–2.96)^***		962 (24.7)	2.89 (2.64–3.16)^***	2.83 (2.58–3.11)^***		431 (11.1)		3.26 (2.86–3.72)^***	3.14 (2.74–3.60)^***
Smoking × being bullied				P^*				P^*					P^*
No × no	3142 (21.5)	Ref	Ref	< 0.001	1416 (9.7)	Ref	Ref	< 0.001	459(3.1)		Ref	Ref	< 0.001
Yes × yes	149 (70)	6.67 (4.97–8.96)^***	6.23 (4.60–8.43)^***	< 0.001	122 (57.3)	9.23 (7.01–12.14)^***	8.17 (6.15–10.85)^***	< 0.001	92 (43.2)		15.19 (11.49–20.08)^***	11.98 (8.92–16.09)^***	< 0.001

OR is odds ratio, CI is confidence interval; ^***P < 0.001
P^* is value of interaction between smoking and being bullied on suicidal behaviors in multiplicative model
^a Adjusted for gender, grade, any siblings, residential background, accommodation type, father’s education level, mother’s education level, self-reported family economical, and number of friends