Table 3

Impact of topic of text-only e-cigarette warning

	Topic of text-only warning
	(1) Nicotine addiction Mean (SD)	(2) Hazard Mean (SD)	(3) Hazard + harm Mean (SD)	1 vs 2 d	2 vs 3 d
Intended effects
Attention to message	3.40 (1.13)	3.81 (.99)	3.78 (1.02)	0.39**	−0.03
Believability	4.17 (.91)	3.52 (1.00)	3.62 (1.06)	−0.68**	0.10
Negative affect	2.30 (1.12)	2.69 (1.06)	2.54 (1.15)	0.36**	−0.14
Anticipated social interactions	2.28 (1.33)	2.71 (1.34)	2.67 (1.33)	0.32**	−0.03
Cognitive elaboration	3.03 (1.31)	3.49 (1.21)	3.50 (1.29)	0.36**	0.02
Interest in e-cigarette use (current users only)	2.39 (.75)	2.31 (.73)	2.29 (.79)	−0.11	−0.03
Perceived message effectiveness	3.13 (1.09)	3.69 (1.00)	3.63 (1.10)	0.53**	−0.06
Unintended effects
Message reactance	2.44 (1.03)	2.81 (1.01)	2.83 (1.16)	0.36**	0.02
Anticipated message avoidance	2.50 (1.18)	2.58 (1.19)	2.62 (1.25)	0.06	0.03
Interest in cigarette use (current smokers only)	2.30 (.69)	2.32 (.73)	2.33 (.72)	0.02	0.02
	%	%	%	h	h
Interest in cigarette use (non-smokers only)	5	7	7	0.08	0.01

d, standardised mean difference; h, standardised proportion difference. Risk belief findings appear in online supplementary table S2 and S3.
**p<0.001.