Table 1

Nicotine replacement therapy (NRT) trials with final end points more than one year after treatment

Study	Time of final follow-up	NRT product*	Dose	Control condition†	Maximum period of NRT use	Abstinence criterion‡	Biochemical verification§
*Gum, nicotine chewing gum; NNS, nicotine nasal spray; Patch, nicotine transdermal patch.
†In addition to placebo, control group received the same counselling and support as NRT group. This varied in type and intensity across studies.
‡Continuous = no smoking after start of outcome observation period. Sustained = continuous abstinence but allowing some very limited smoking lapses throughout the follow-up period. PP (point prevalence) = abstinence from smoking in the week before follow up.
§CO, expired-air carbon monoxide; Cot, saliva cotinine.
¶CO verification not conducted in all clinical centres in study.
Blondal 1989	2 years	Gum	4 mg	Placebo	12 weeks	Continuous	None
Blondal 1997	2 years	NNS	0.5 mg	Placebo	52 weeks	Continuous	CO <10 ppm
Blondal 1999	6 years	NNS	0.5 mg	Placebo	52 weeks	Sustained	CO <10 ppm
Clavel 1997	4 years	Gum	2 mg	Placebo	26 weeks	Sustained	CO <10 ppm
Daughton 1999	4.6 years	Patch	21 mg/24 h	Placebo	12 weeks	Sustained	CO <10 ppm¶
Glavas 2003	5 years	Patch	21 mg/24 h	Placebo	3 weeks	PP	CO <10 ppm
Herrera 1995	2 years	Gum	2 mg	Placebo	12 weeks	Sustained	CO <10 ppm
Mikkelsen 1994	3 years	Patch	15 mg/16 h	Placebo	16 weeks	Sustained	CO <10 ppm
Richmond 1997	3 years	Patch	21 mg/24 h	Placebo	10 weeks	Continuous	CO <10 ppm
Stapleton 1998	3.3 years	NNS	0.5 mg	Placebo	52 weeks	Sustained	CO <10 ppm
Tonnesen 1988	2 years	Gum	2 mg	Placebo	16 weeks	Continuous	CO<10ppm
Yudkin 2003	8 years	Patch	21 mg/24 h	Placebo	12 weeks	Continuous	Cot <15 ng/ml