Table 3.

Generalized estimating equation model for predicting 6-month abstinence (2,837 observations and 2,297 individuals)

	Step 1. Adjusted odds ratio (95% CI)	Step 2. Adjusted odds ratio (95% CI)	Step 3. Adjusted odds ratio (95% CI)
Delay
On the day	Ref	Ref	Ref
1–6 days	0.65 (0.52–0.82)	0.72 (0.56–0.91)	0.78 (0.61–1.00)
1 week or more	1.13 (0.91–1.41)	1.07 (0.85–1.35)	1.03 (0.81–1.32)
Already stopped	0.93 (0.70–1.23)	0.91 (0.68–1.23)	0.92 (0.68–1.25)
Gender
Female	Ref	Ref	Ref
Male	1.09 (0.91–1.31)	1.11 (0.92–1.34)	1.20 (0.99–1.48)
Age (years)
18–24	Ref	Ref	Ref
25–39	1.39 (0.83–2.34)	1.53 (0.88–2.68)	1.61 (0.93–2.79)
40–54	1.04 (0.62–1.74)	1.24 (0.71–2.15)	1.42 (0.83–2.44)
55+	1.17 (0.70–1.96)	1.50 (0.86–2.60)	1.71 (0.99–2.94)
Socioeconomic status
Low	Ref	Ref	Ref
Moderate	1.12 (0.90–1.40)	1.07 (0.85–1.34)	1.07 (0.84–1.37)
High	1.33 (1.06–1.66)	1.14 (0.91–1.44)	1.19 (0.93–1.51)
Country
Canada	Ref	Ref	Ref
US	1.24 (0.94–1.64)	1.24 (0.94–1.64)	1.38 (1.03–1.85)
UK	1.74 (1.34–2.26)	1.55 (1.19–2.03)	1.66 (1.25–2.20)
Australia	1.40 (1.09–1.80)	1.35 (1.04–1.75)	1.55 (1.18–2.04)
Wave
5	Ref	Ref	Ref
6	0.89 (0.76–1.05)	0.85 (0.71–1.01)	0.82 (0.68–0.99)
Nicotine dependence
Low	Ref	Ref	Ref
Moderate	—	0.75 (0.60–0.93)	0.79 (0.63–0.99)
High	—	0.54 (0.41–0.70)	0.57 (0.43–0.75)
Used medication to stop smoking
No	Ref	Ref	Ref
Yes	—	1.02 (0.84–1.23)	1.00 (0.82–1.23)
Made other attempt/s since last survey
No	Ref	Ref	Ref
Yes	—	0.32 (0.26–0.39)	0.49 (0.39–0.61)
Method to quit
Stopped abruptly		Ref	Ref
Cut down to quit		0.68 (0.55–0.84)	0.77 (0.62–0.96)
Quit attempt recency
< 1month	Ref	Ref	Ref
1–3 months	—	—	1.43 (0.97–2.11)
4–6 months	—	—	2.22 (1.50–3.29)
>6 months	—	—	6.15 (4.25–8.91)