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Table 14 Meta-analyses by type of cigarette smoked a

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

Type of cigarette smoked Statisticb All lung cancerc Squamousd Adenoe
Only filter vs. only plainf n 42 13 10
  F 0.67 (0.64-0.72) 0.58 (0.52-0.64) 0.88 (0.75-1.03)
  R 0.69 (0.61-0.78) 0.52 (0.40-0.68) 0.84 (0.66-1.08)
  H, PH 3.18, p < 0.001 4.73, p < 0.001 1.90, p < 0.05
Ever filter vs. only plaing n 42 11 10
  F 0.79 (0.75-0.83) 0.85 (0.79-0.91) 1.00 (0.89-1.12)
  R 0.73 (0.65-0.82) 0.55 (0.41-0.74) 0.99 (0.84-1.16)
  H, PH 3.60, p < 0.001 7.73, p < 0.001 1.35, NS
Only filter vs. ever plainh n 42 13 10
  F 0.67 (0.63-0.71) 0.87 (0.81-0.92) 1.05 (0.93-1.18)
  R 0.70 (0.62-0.78) 0.69 (0.57-0.83) 0.98 (0.80-1.21)
  H, PH 3.30, p < 0.001 3.15, p < 0.001 1.88, p < 0.05
Handrolled vs. manufacturedi n 20 5 4
  F 1.27 (1.16-1.40) 1.47 (1.24-1.76) 2.12 (1.53-2.96)
  R 1.29 (1.12-1.49) 1.62 (1.18-2.21) 2.09 (0.83-5.25)
  H, PH 1.81, p < 0.05 2.61, p < 0.05 6.54, p < 0.001
Mentholated vs. non-mentholated n 6 1 1
  F 0.99 (0.86-1.14) 1.04 (0.75-1.44) 0.96 (0.73-1.27)
  R 0.98 (0.80-1.20) 1.04 (0.75-1.44) 0.96 (0.73-1.27)
  H, PH 1.89, p < 0.1 NA NA
  1. a Within each study, results for the relevant smoking product and smoking status are selected in the following preference order, within each sex, for:
  2. cigarette type – see notes f to i;
  3. unexposed group – see notes f to i;
  4. smoking product – any, cigarettes (ignoring other products), cigarettes only;
  5. smoking status – ever, current;
  6. lung cancer type – see notes c to e;
  7. race – all or nearest available, otherwise by race;
  8. follow-up period – longest available;
  9. overlapping studies – principal, subsidiary;
  10. age – whole study, widest available age group;
  11. Results are then selected for:
  12. sex – single sex results, combined sex results;
  13. adjustment for potential confounders – most available.
  14. 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 < 0.05, p < 0.1 or NS (p ≥ 0.1), PB = probability value for between levels (see Methods) similarly expressed.
  15. c All or nearest available, must include at least squamous cell carcinoma and adenocarcinoma.
  16. d Squamous cell carcinoma or nearest available, but not including adenocarcinoma.
  17. e Adenocarcinoma or nearest available, but not including squamous cell carcinoma.
  18. f Or nearest available.
  19. Preference order for cigarette type – filter only/NOS, always, mainly, both, equally, ever.
  20. Preference order for comparison group – plain only/NOS, always, mainly, ever.
  21. g Or nearest available.
  22. Preference order for cigarette type – filter ever, equally, both, mainly, always, only/NOS.
  23. Preference order for comparison group – plain only/NOS, always, mainly, ever.
  24. h Or nearest available.
  25. Preference order for cigarette type – filter only/NOS, always, mainly, both, equally, ever.
  26. Preference order for comparison group – plain ever, mainly, always, only/NOS.
  27. i Preference order for cigarette type – handrolled any, both, mainly, only.
  28. Preference order for comparison group – manufactured only ever, only current, any, ever.
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