Table 3.

Predictors of consent at baseline and completion of the 3-month follow-up (n = 1246)

	Consented to follow-up		Completed follow-up
Predictors	Adjusted risk ratio (95% CI)	P-value	Adjusted risk ratio (95% CI)	P-value
Incentive schemes		0.18		0.20
No incentive	Ref		Ref
Promised HK$100	0.92 (0.75–1.13)	0.92	1.07 (0.79–1.45)	0.65
Promised HK$200	1.09 (0.89–1.34)	0.46	1.23 (0.91–1.66)	0.18
Mixed incentive	1.14 (0.94–1.38)	0.20	1.33 (1.00–1.77)	0.05
Sex
Female	Ref		–	–
Male	1.30 (1.08–1.57)	<0.01	–	–
Age group (years)		0.49
15–29	Ref
30–39	1.02 (0.75, 1.38)	0.90	–	–
40–49	1.02 (0.77, 1.36)	0.87	–	–
50–59	1.03 (0.78, 1.37)	0.84	–	–
60–65	0.78 (0.53, 1.15)	0.21	–	–
Above 65	1.05 (0.71, 1.55)	0.81	–	–
Education level		<0.01		0.08
Primary or below	Ref		Ref
Secondary	1.45 (1.14–1.84)	<0.01	1.32 (0.98–1.79)	0.07
Tertiary	1.66 (1.27–2.17)	<0.01	1.47 (1.05–2.07)	0.03
Employment status		0.14
Employed	Ref		–	–
Others	1.17 (0.93–1.49)	0.17	–	–
Retired	1.27 (0.95–1.68)	0.12	–	–
Had children under 16	1.28 (1.07–1.54)	<0.01	–	–
Place of birth		0.01		<0.01
Hong Kong	Ref		Ref
China Mainland	0.80 (0.67–0.95)	<0.01	0.74 (0.58–0.93)	0.01
Other places	0.57 (0.32–1.00)	0.05	0.34 (0.12–1.01)	0.05
Intention to quit		<0.01		0.08
No intention	Ref		Ref
Quit after 30 days	1.37 (1.13–1.65)	<0.01	1.13 (0.84–1.52)	0.43
Quit within 30 days	1.31 (1.11–1.54)	<0.01	1.30 (1.04–1.62)	0.02
Ever used Ecigs or HTP
No	Ref		–	–
Yes	1.07 (0.89–1.28)	0.49	–	–

HK$100 = US$12.8; Ecigs or HTP: E-cigarettes or heated tobacco products; Baseline predictors shown in the table had p-value below 0.1 in the univariate analysis. Other variables with p-value 0.1 or higher were not included in the multivariate models