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)

Sponsiello-Wang et al. BMC Cancer 2008 8:356   doi:10.1186/1471-2407-8-356

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