Full Report - Food, Nutrition, and the Prevention of Cancer

CHAPTER 4 • FOODS AND DRINKS
Figure 4.2.12 Raw vegetables and stomach cancer;
cohort and case-control studies
Cohort
Botterweck 1998 0.51 (0.05–4.73)
Galanis 1998 0.81 (0.53–1.23)
Khan 2004 Men 0.63 (0.16–2.51)
Khan 2004 Women 2.03 (0.14–29.46)
Summary estimate 0.80 (0.54–1.18)
Case control
Jedrychowski 1981 0.10 (0.02–0.41)
Jedrychowski 1986 1.56 (0.12–20.74)
Buiatti 1989 0.56 (0.45–0.71)
Caggon 1989 0.13 (0.01–2.88)
Kato 1990 Men 0.59 (0.38–0.91)
Kato 1990 Women 0.86 (0.48–1.48)
Hoshiyama and Sasaba 1992 0.44 (0.29–0.68)
Ramon 1993 0.35 (0.16–0.78)
Cornee 1995 0.27 (0.10–0.72)
Huang 1999 0.77 (0.62–0.94)
De Stefani 2001 0.46 (0.16–1.34)
Sriamporn 2002 0.40 (0.01–15.73)
Lee 2003 0.11 (0.04–0.27)
Lissowska 2004 0.82 (0.52–1.28)
Summary estimate 0.50 (0.38–0.65)
0.5 1 2
Relative risk, per 100 g/day
Relative risk (95% CI)
intake group when compared to the lowest). 241
Most case-control studies showed decreased risk with
increased intake, which was statistically significant in 10. 58
109 152 156 164 171 232 246-248 No studies showed statistically significant
increased risk. Meta-analysis was possible on 6 casecontrol
studies, giving a summary effect estimate of 0.40
(95% CI 0.19–0.82) per 100 g/day, with high hetero-
109 152 171 232 244 250
geneity.
White or pale vegetables
This incorporates a wide range of vegetables. For example,
in Japan white vegetables such as daikon (radish) are commonly
consumed. Descriptions used for this exposure were
white vegetables, pale green or light green vegetables, and
raw chicory.
Both cohort studies showed non-significant decreased risk
with increased intake. 150 214 Meta-analysis was possible on
both studies, giving a summary effect estimate of 0.49 (95%
CI 0.24–1.01) per 100 g/day, with no heterogeneity (figure
4.2.11).
All six case-control studies showed decreased risk with
increased intake, 157 165 169 226 228 243 which was statistically significant
in three. 165 169 243 Meta-analysis was possible on three
studies, giving a summary effect estimate of 0.57 (95% CI
0.32–1.02) per 100 g/day, with high heterogeneity, which
was caused by varying size, not direction of the effect (figure
4.2.11).
Figure 4.2.13 Raw vegetables and stomach cancer;
case-control studies: dose response
Jedrychowski 1981
Jedrychowski 1986
Buiatti 1989
Coggon 1989
Kato 1990 Men
Kato 1990 Women
Hoshiyama and Sasaba 1992
Ramon 1993
Cornee 1995
Huang 1999
De Stefani 2001
Sriamporn 2002
Lee 2003
0 50 100
150
Raw vegetables (g/day)
Raw vegetables
Of seven independent estimates from six cohort studies that
reported on raw vegetables, four reported non-significant
reduced risk, 146 214 253 254 two reported non-significant
increased risk, 214 252 and the other reported a significant
increased risk. 148 Two of the increased risk estimates, including
the one that reached statistical significance, were stratified
for women only. Meta-analysis was possible on four
estimates from three studies (not including the one that was
statistically significant), giving a summary effect estimate of
0.80 (95% CI 0.54–1.18) per 100 g/day, with no heterogeneity
(figure 4.2.12).
Of the 25 case-control studies that reported on raw veg-
109 129 161 162 167 172 174 183
etables, 21 reported decreased risk,
184 191 219 225 226 243 247 248 250 255 256 258 260 261 264 which was sta-
129 161 172 174 225 226 243 247 248 256 260 261
tistically significant in 13.
264 None of the remaining 4 studies that reported increased
risk reached statistical significance. 257 259 262 263 Meta-analysis
was possible on 14 independent estimates from 13 casecontrol
studies, giving a summary effect estimate of 0.50
(95% CI 0.38–0.65) per 100 g/day, with moderate heterogeneity
(figure 4.2.12).
A dose-response relationship was apparent from casecontrol
but not cohort data (figure 4.2.13).
Of the three ecological studies, two reported statistically significant
reduced risk208 238 and one reported a non-significant
increased risk with increased raw vegetable consumption. 202
89