Table 4.

Results of logistic modelling of positive shift (versus no change or a negative change) in stage of change, according to heaviness of smoking

	<20 cigarettes per day			⩾20 cigarettes per day
Intervention	Regression ratio (95% CI)	P value		Regression ratio (95% CI)	P value
Tailored letter v control	0.92 (0.67 to 1.25)	0.58		1.76 (1.11 to 2.80)	0.02
Non-tailored letter v control	1.17 (0.87 to 1.56)	0.31		1.10 (0.67 to 1.82)	0.71