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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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