Table 5.

Predicting sustained quitting (quit > 1 month) at wave N + 1 using dependence measures from wave N

Wave N + 1 quit (>1 month)	Wave N measure	Categorical versions of predictors			Continuous versions of predictors
		Unadjusted	Adjusteda	R2	Unadjusted	Adjusteda	R2
		OR (95% CI)	OR (95% CI)		OR (95% CI)	OR (95% CI)
W2—quit	W1—CPD	0.69 (0.62–0.76)**	0.84 (0.74–0.96)*	.066	0.73 (0.69–0.78)**	0.84 (0.77–0.92)**	.079
	W1—TTFC	1.46 (1.34–1.59)**	1.33 (1.20–1.48)**		1.34 (1.26–1.42)**	1.19 (1.10–1.29)**
	W1—HSI	0.78 (0.74–0.82)**	0.79 (0.74–0.83)**	.065	0.85 (0.82–0.87)**	0.85 (0.82–0.88)**	.080
W3—quit	W2—CPD	0.60 (0.54–0.67)**	0.71 (0.62–0.81)**	.105	0.74 (0.69–0.79)**	0.81 (0.74–0.88)**	.099
	W2—TTFC	1.47 (1.35–1.60)**	1.24 (1.12–1.37)**		1.29 (1.21–1.37)**	1.12 (1.04–1.21)*
	W2—HSI	0.75 (0.71–0.79)**	0.76 (0.72–0.81)**	.104	0.85 (0.82–0.88)**	0.86 (0.83–0.89)**	.099
W4—quit	W3—CPD	0.61 (0.55–0.68)**	0.72 (0.63–0.82)**	.091	0.71 (0.66–0.77)**	0.76 (0.69–0.84)**	.097
	W3—TTFC	1.47 (1.35–1.61)**	1.27 (1.14–1.41)**		1.30 (1.22–1.38)**	1.12 (1.04–1.21)*
	W3—HSI	0.75 (0.71–0.80)**	0.76 (0.72–0.80)**	.090	0.84 (0.81–0.87)**	0.84 (0.81–0.87)**	.095

Note. CPD = cigarettes per day; HSI = Heaviness of Smoking Index; OR = odds ratio; TTFC = time to first cigarette.

^aControlling for the “other” heaviness of smoking measure (i.e., for CPD, the “other” measure is TTFC and vice versa) where appropriate and socio-demographic factors: cohort (for smoking status at Waves 3 and 4), country, sex, age, education, and income.

R² = Nagelkerke’s adjusted R².

*p < .01; **p < .001.