1 All tobacco abstinence at longest follow‐up Show forest plot

2

Odds Ratio (M‐H, Fixed, 95% CI)

Subtotals only

1.1 6 months or greater continous abstinence

2

293

Odds Ratio (M‐H, Fixed, 95% CI)

0.86 [0.47, 1.57]

1 6 months or greater abstinence, strictest criteria Show forest plot

6

1341

Odds Ratio (M‐H, Fixed, 95% CI)

1.12 [0.87, 1.43]

1.1 Nicotine Patch

4

1031

Odds Ratio (M‐H, Fixed, 95% CI)

1.16 [0.88, 1.54]

1.2 Nicotine Gum

2

310

Odds Ratio (M‐H, Fixed, 95% CI)

0.98 [0.59, 1.63]

1 Abstinence from all tobacco use (where reported) at 6 months or more Show forest plot

12

8149

Odds Ratio (M‐H, Fixed, 95% CI)

1.59 [1.40, 1.80]

1.1 Randomisation by organisation

5

2670

Odds Ratio (M‐H, Fixed, 95% CI)

1.38 [1.15, 1.67]

1.2 Individual randomisation

7

5479

Odds Ratio (M‐H, Fixed, 95% CI)

1.76 [1.49, 2.08]

2 Sensitivity analysis: Abstinence from smokeless tobacco use (where reported) at 6 months or more Show forest plot

12

8149

Odds Ratio (M‐H, Fixed, 95% CI)

1.61 [1.43, 1.82]

2.1 All tobacco use

4

4446

Odds Ratio (M‐H, Fixed, 95% CI)

1.72 [1.41, 2.09]

2.2 Smokeless tobacco use

8

3703

Odds Ratio (M‐H, Fixed, 95% CI)

1.55 [1.33, 1.81]

3 Subgroup analysis: Use of oral examination and feedback Show forest plot

12

Odds Ratio (M‐H, Random, 95% CI)

Subtotals only

3.1 Intervention included oral examination and feedback

5

2455

Odds Ratio (M‐H, Random, 95% CI)

1.92 [1.14, 3.23]

3.2 Oral examination not part of the intervention

7

5694

Odds Ratio (M‐H, Random, 95% CI)

1.59 [1.21, 2.09]

4 Subgroup analysis: Use of telephone support Show forest plot

12

Odds Ratio (M‐H, Random, 95% CI)

Subtotals only

4.1 Telephone support for intervention, not for control

8

3953

Odds Ratio (M‐H, Random, 95% CI)

2.09 [1.68, 2.61]

4.2 No telephone support for either condition

3

3893

Odds Ratio (M‐H, Random, 95% CI)

1.18 [0.81, 1.73]

4.3 Telephone support for control group only

1

303

Odds Ratio (M‐H, Random, 95% CI)

1.29 [0.54, 3.05]

5 Subgroup analysis: Motivation Show forest plot

12

Odds Ratio (M‐H, Fixed, 95% CI)

Subtotals only

5.1 Motivated

4

4116

Odds Ratio (M‐H, Fixed, 95% CI)

1.60 [1.32, 1.95]

5.2 Not selected by motivation

8

4033

Odds Ratio (M‐H, Fixed, 95% CI)

1.58 [1.35, 1.85]

6 Behavioural intervention +/‐ pharmacotherapy versus minimal contact. Long term cessation Show forest plot

1

210

Odds Ratio (M‐H, Fixed, 95% CI)

1.48 [0.80, 2.73]

6.1 Nicotine gum

1

106

Odds Ratio (M‐H, Fixed, 95% CI)

2.46 [0.99, 6.12]

6.2 Placebo gum

1

104

Odds Ratio (M‐H, Fixed, 95% CI)

0.91 [0.38, 2.18]