Comparison 8. 4 mg versus 2 mg gum.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
8.1 Smoking cessation	5	856	Risk Ratio (M‐H, Fixed, 95% CI)	1.43 [1.12, 1.83]
8.1.1 High‐dependency smokers	4	618	Risk Ratio (M‐H, Fixed, 95% CI)	1.85 [1.36, 2.50]
8.1.2 Low‐dependency smokers	3	238	Risk Ratio (M‐H, Fixed, 95% CI)	0.77 [0.49, 1.21]
8.2 Palpitations	1		Risk Ratio (M‐H, Fixed, 95% CI)	Totals not selected
8.3 Treatment withdrawals	2	465	Risk Ratio (M‐H, Fixed, 95% CI)	1.08 [0.18, 6.36]