A prospective cohort study on vegetable and fruit consumption and stomach cancer risk in The Netherlands.

Department of Epidemiology, Maastricht University, The Netherlands.The association between vegetable and fruit consumption and stomach cancer risk was investigated in the Netherlands Cohort Study among 120,852 men and women aged 55-69 years at the start in September 1986. Analyses were based on 282 incident stomach cancer cases after 6.3 years of follow-up. Age- and sex-adjusted rate ratios of stomach cancer in increasing quintiles of combined vegetable and fruit consumption were 1.00, 0.70, 0.65, 0.76, and 0.64 (p trend = 0.04). Multivariate analysis resulted in rate ratios that were somewhat closer to one (p trend = 0.14). Furthermore, inverse associations for total vegetables, pulses, raw leafy vegetables, total fruit, citrus fruit, and apples and pears that were observed in crude analyses became weaker or disappeared in multivariate analyses. Total vegetable, but not fruit, consumption was significantly lower in cases diagnosed in the first follow-up year. In analyses limited to first year cases (resembling a case-control study), rate ratios for increasing tertiles of total vegetable consumption were 1.00, 0.17, and 0.18 (p trend = 0.0001), which may indicate the presence of information bias in case-control studies. This prospective study suggests that vegetable and fruit consumption was not clearly associated with stomach cancer risk in the Dutch population. The findings of this study are comparable with findings of other cohort studies, but they do not support the findings of case-control studies