Table 4.

Cox proportional hazards model predicting time to relapse on most recent quit attempt, among current smokers who made a quit attempt in the past year (TUS-CPS 2010–2011, N= 9249). Note: HR>1 indicates faster relapse.

	Adjusted hazard ratio (95% CI)
Tobacco use status
Exclusive smokers (reference)	1
Dual users	1.13 (1.02–1.26)*
Cigarette consumption
< 12 cigarettes per month (reference)	1
0 to 10 cigarettes per day	1.49 (1.41–1.56)***
11 to 20 cigarettes per day	1.70 (1.61–1.79)***
≥ 21 cigarettes per day	1.95 (1.79–2.13)***
Smoking within 30 minutes of waking	NA
Time to first cigarette within tobacco use statusc
Exclusive smokers and time to first cigarette ≥30 minutes after waking	1
Exclusive smokes and time to first cigarette < 30 minutes after waking	1.20 (1.16–1.25)***
Dual users and time to first cigarette ≥30 minutes after waking	1
Dual users and time to first cigarette < 30 minutes after waking	1.00 (0.84–1.20)
Age
18–24 years (reference)	1
25–34 years	0.98 (0.93–1.04)
35–49 years	1.06 (1.00–1.12)*
50–64 years	1.07 (1.02–1.13)*
≥ 65 years	1.02 (0.94–1.08)
Sex
Female (reference)	1
Male	0.99 (0.96–1.02)
Race/ethnicity
White (reference)	1
Hispanic	0.93 (0.88–0.99)*
African American	0.93 (0.88–0.97)**
Asian/PI	0.93 (0.88–0.99)
Mixed/Other	1.09 (0.99–1.20)
Education
< High school (reference)	1
High school	1.01 (0.97–1.08)
Some college	1.02 (0.97–1.08)
College graduate	0.98 (0.92–1.04)
Age of smoking initiation (regular use)
Age of smoking initiation > 15 years (reference)	1
Age of smoking initiation ≤ 15 years	0.97 (0.93–1.00)

^*p < 0.05

^**p< 0.005

^***p<0.001

p-value for interaction term between tobacco use status and consumption = 0.32

^cp-value for interaction term between tobacco use status and time to first cigarette after waking = 0.06