Amount smoked | Statisticb
| All lung cancerc
| Squamousd
| Adenoe
|
|---|
Number of setsf
| | 190 | 48 | 46 |
About 5 cigs/dayg
| n | 174 | 41 | 39 |
| | F | 3.25 (3.17-3.34) | 6.07 (5.50-6.70) | 2.70 (2.47-2.96) |
| | R | 3.49 (3.13-3.89) | 4.98 (3.93-6.31) | 1.83 (1.40-2.39) |
| | H, PH
| 10.77, p < 0.001 | 3.85, p < 0.001 | 6.19, p < 0.001 |
About 20 cigs/dayh
| n | 113 | 30 | 28 |
| | F | 5.30 (5.18-5.43) | 12.36 (10.89-14.03) | 3.58 (3.18-4.04) |
| | R | 7.33 (6.29-8.54) | 11.86 (8.92-15.76) | 2.73 (2.06-3.61) |
| | H, PH
| 22.45, p < 0.001 | 3.72, p < 0.001 | 4.27, p < 0.001 |
About 45 cigs/dayi
| n | 128 | 37 | 34 |
| | F | 10.17 (9.89-10.45) | 28.95 (25.42-32.98) | 7.20 (6.38-8.13) |
| | R | 13.69 (11.80-15.89) | 27.65 (20.42-37.44) | 4.80 (3.29-7.01) |
| | H, PH
| 14.89, p < 0.001 | 3.98, p < 0.001 | 7.69, p < 0.001 |
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a Within each study, results are selected in the following preference order, within each sex, for:
- smoking status – ever, current;
- smoking product – any, cigarettes (ignoring other products), cigarettes only;
- cigarette type – any, manufactured (with or without handrolled), manufactured only;
- unexposed group – never any product, never cigarettes, near equivalent (see Methods);
- follow-up period – longest available;
- lung cancer type – see notes c to e;
- race – all or nearest available, otherwise by race;
- overlapping studies – principal, subsidiary;
- age – whole study, widest available age group;
- Results are then selected for:
- sex – single sex results, combined sex results;
- adjustment for potential confounders – most available.
- Results are by number of cigarettes or cigarette equivalents.
-
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).
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c All or nearest available, must include at least squamous cell carcinoma and adenocarcinoma.
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d Squamous cell carcinoma or nearest available, but not including adenocarcinoma.
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e Adenocarcinoma or nearest available, but not including squamous cell carcinoma.
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f Number of sets of RRs available for the key value analysis, where base for comparison is never smoked.
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g Category for which results are provided includes 5 cigs/day but does not include 20 cigs/day.
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h Category for which results are provided includes 20 cigs/day but does not include 5 or 45 cigs/day.
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i Category for which results are provided includes 45 cigs/day but does not include 20 cigs/day.
