Vegetable intake and pancreatic cancer risk: the multiethnic cohort study

Investigators studying associations between vegetable intake and pancreatic cancer risk have reported inconsistent findings to date. To further explore these associations, the authors analyzed data on 183,522 participants enrolled in the Hawaii-Los Angeles Multiethnic Cohort Study in 1993-1996. Intakes of total vegetables, light green, dark green, yellow-orange, and cruciferous vegetables, tomato products, and legumes were estimated from a quantitative food frequency questionnaire. After an average of 8.3 years of follow-up, 529 pancreatic cancer cases were identified. Multivariate-adjusted Cox proportional hazards models were created. All statistical tests were two-sided. Overall, total vegetable intake was not associated with pancreatic cancer risk, nor was intake of vegetable subgroups. Current smokers, who were at increased risk of pancreatic cancer (relative risk = 1.78, 95% confidence interval: 1.40, 2.27), had a decreased risk with higher intake of dark green vegetables (for comparison of extreme quartiles, relative risk = 0.50, 95% confidence interval: 0.27, 0.92; p-trend = 0.029). The inverse association for dark green vegetables was also seen in African Americans (p-trend = 0.043). In stratified analyses, inverse associations with total vegetables, light green vegetables, and legumes were significant in overweight/obese subjects. In conclusion, the authors found no evidence for an inverse association between vegetable intake and pancreatic cancer overall, but inverse associations in high-risk persons suggest the need for further investigation.