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Table 6 Some alternative meta-analyses for ever smoking compared to those in Table 5

From: Systematic review with meta-analysis of the epidemiological evidence in the 1900s relating smoking to lung cancer

Analysis description

Statisticb

All lung cancerc

Squamousd

Adenoe

As Table 5 a

n

328

102

107

 

F

4.22 (4.16-4.28)

9.52 (8.94-10.13)

3.44 (3.27-3.61)

 

R

5.50 (5.07-5.96)

10.47 (8.88-12.33)

2.84 (2.41-3.35)

 

H, PH

22.84, p < 0.001

5.17, p < 0.001

8.78, p < 0.001

Using more precise outcome definitionf

n

317

74

87

 

F

4.23 (4.17-4.29)

10.43 (9.72-11.20)

3.58 (3.39-3.78)

 

R

5.59 (5.15-6.07)

11.56 (9.68-13.81)

2.99 (2.49-3.58)

 

H, PH

23.48, p < 0.001

4.18, p < 0.001

9.18, p < 0.001

Using least rather than most adjusted estimates

n

331

102

107

 

F

4.23 (4.17-4.29)

9.49 (8.93-10.09)

3.38 (3.21-3.55)

 

R

5.48 (5.06-5.93)

10.37 (8.83-12.18)

2.83 (2.39-3.34)

 

H, PH

23.36, p < 0.001

5.23, p < 0.001

9.57, p < 0.001

Omitting study LIU4

n

326

NAg

NAg

 

F

6.47 (6.34-6.60)

  
 

R

5.52 (5.10-5.97)

  
 

H, PH

12.54, p < 0.001

  

Preferring results for cigarettes to results for any product

n

327

102

107

 

F

4.73 (4.66-4.80)

9.48 (8.91-10.08)

3.43 (3.27-3.61)

 

R

5.49 (5.10-5.92)

10.44 (8.88-12.29)

2.82 (2.39-3.32)

 

H, PH

19.39, p < 0.001

5.12, p < 0.001

8.72, p < 0.001

Selecting results for cigarettes onlyh

n

54

11

11

 

F

4.37 (4.28-4.47)

9.05 (7.84-10.45)

1.93 (1.70-2.18)

 

R

6.45 (5.41-7.70)

11.50 (7.47-17.69)

2.87 (1.49-5.55)

 

H, PH

22.68, p < 0.001

4.57, p < 0.001

16.64, p < 0.001

Selecting results specific for age <56 years

n

38

10

10

 

F

5.79 (5.15-6.51)

11.04 (7.08-17.20)

4.94 (3.73-6.56)

 

R

6.57 (4.94-8.74)

14.73 (6.83-31.76)

4.17 (1.86-9.35)

 

H, PH

4.17, p < 0.001

2.35, p < 0.05

7.00, p < 0.001

Selecting results specific for age 50–70 years

n

31

6

4

 

F

5.77 (5.29-6.29)

16.32 (11.11-23.95)

5.62 (3.91-8.07)

 

R

6.46 (4.99-8.35)

17.30 (10.78-27.74)

5.31 (3.20-8.79)

 

H, PH

7.67, p < 0.001

1.37, NS

1.14, NS

Selecting results specific for age 65+ years

n

37

2

2

 

F

2.88 (2.78-3.00)

15.00 (6.46-34.80)

1.73 (0.99-3.02)

 

R

5.48 (4.59-6.55)

15.00 (6.46-34.80)

1.73 (0.99-3.02)

 

H, PH

9.66, p < 0.001

0.02, NS

0.19, NS

  1. a See Table 5 for details of the definition of this analysis.
  2. b n = number of estimates combined, F = fixed-effect meta-analysis RR (95% CI), R = random-effects meta-analysis RR (95% CI), H = heterogeneity chisquared per degree of freedom, PH = probability value for heterogeneity expressed as p < 0.001, p < 0.01, p < 0.05, p < 0.1 or NS (p ≥ 0.1), PB = probability value for between levels (see methods) similarly expressed.
  3. c All or nearest available, must include at least squamous cell carcinoma and adenocarcinoma.
  4. d Squamous cell carcinoma or nearest available, but not including adenocarcinoma.
  5. e Adenocarcinoma or nearest available, but not including squamous cell carcinoma.
  6. f Only including results for all lung cancer, squamous cell carcinoma specifically, or adenocarcinoma specifically.
  7. g Not applicable as results by histological type were not available for study LIU4.
  8. h See also Table 13 (footnote c).
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