Table 3 Effect of NRT treatment for less than 12 months on relapse after 12 months of smoking cessation.

Study	NRT	Placebo	Weight (%)	OR (95% CI)
Blondal 1989	1/30*	1/22	1.6	0.72 (0.04 to12.2)
Blondal 1997	5/20	2/13	3.8	1.83 (0.30 to 11.3)
Blondal 1999	13/32	3/13	5.9	2.28 (0.52 to 9.92)
Clavel 1997	23/53	11/43	16.7	2.23 (0.93 to 5.35)
Daughton 1999	11/50	4/19	7.7	1.06 (0.29 to 3.84)
Glavas 2003	3/13	1/9	2.1	2.40 (0.21 to 27.7)
Herrera 1995	7/37	4/17	6.6	0.76 (0.19 to 3.05)
Mikkelsen 1994	9/24	2/6	3.6	1.20 (0.18 to 7.93)
Richmond 1997	8/29	6/14	7.2	0.51 (0.13 to 1.93)
Stapleton 1998	14/33	7/14	8.2	0.74 (0.21 to 2.56)
Tonnesen 1988	6/23	7/12	5.9	0.25 (0.06 to 1.11)
Yudkin 2003	43/91	27/62	30.5	1.16 (0.61 to 2.22)
Total	143/435	75/244	100	1.11 (0.78 to 1.59)

Random effects test of overall effect: Z = 0.74, p>0.5.

*Numbers abstinent for 12 months who relapsed before final follow up/numbers abstinent for 12 months.