Table 5.
Meta-analyses of estimates of pancreatic cancer risk associated with ST for never smokers, using overall population estimates if never smoker estimates are not availablea
| Meta-analysis | Estimates Included |
Fixed-effect RR (85% CI) |
Random-effects RR (95% CI) |
Heterogeneity | ||
| Chisquared (d.f.) | I2 | P | ||||
| All studies | 2,6,10,13,18,20,23 | 1.32(0.98–1.77) | 1.14(0.67–1.93) | 16.06 (6) | 62.6 | 0.013 |
| All preferring snuff to chewingb | 2,6,10,13,19,20,26 | 1.35(0.98–1.86) | 1.08(0.64–1.82) | 12.31 (6) | 51.2 | 0.055 |
| USA or Canada | 2,13,18,20,23 | 1.08(0.73–1.58) | 1.00(0.50–2.02) | 11.92 (4) | 66.4 | 0.018 |
| Sweden or Norwayc | 6,10 | 1.78(1.11–2.85) | 1.61(0.77–3.34) | 1.50 (1) | 33.2 | 0.221 |
| Cohort | 2,6,10 | 1.75 (1.20–2.54) | 1.75(1.20–2.54) | 1.51 (2) | 0.0 | 0.470 |
| Case-controld | 13,18,20,23 | 0.81(0.49–1.32) | 0.84(0.36–1.97) | 8.48 (3) | 64.6 | 0.037 |
| Chewing tobacco | 18,23 | 0.97(0.51–1.84) | 1.22(0.27–5.55) | 4.83 (1) | 79.3 | 0.028 |
| Snuff | 6,10,19,26 | 1.54(1.00–2.37) | 1.25(0.64–2.44) | 4.54 (3) | 33.9 | 0.209 |
| ST unspecified | 2,13,20 | 1.14(0.70–1.84) | 0.89(0.33–2.40) | 6.94 (2) | 71.2 | 0.031 |
| Never smoking exclusively | 6,10,18,20,23 | 1.39(0.98–1.99) | 1.28(0.71–2.30) | 8.80 (4) | 54.5 | 0.066 |
| Excluding Third National Cancer Survey Study [16] | 2,6,10,18,20,23 | 1.46(1.08–1.99) | 1.38(0.88–2.15) | 9.10 (5) | 45.0 | 0.105 |
a See Table 3 for the individual study estimates
b Where estimates for both snuff and chewing are available
c There was no significant variation by continent (chisquared = 2.64 on 1 d.f., p = 0.104)
d There was significant variation by study type (chisquared = 6.07 on 1 d.f., p = 0.014)