Fluid Intake and Colorectal Cancer Risk in the Netherlands Cohort Study

Abstract

Total fluid intake, specifically water intake, has been suggested to protect against colorectal cancer. We examined the association of total fluid intake with colorectal cancer endpoints and possible effect modification by fiber intake within the Netherlands Cohort Study (N = 120,852). We also investigated intake of specific beverages. After 13.3 yr, 1,443 male and 1,040 female colorectal cancer cases with complete baseline questionnaires were available for case-cohort analyses. Multivariate analyses showed no dose-response relationship of total fluid intake and intake of specific beverages with the risk of overall colorectal, proximal, and distal colon cancer. For rectal cancer risk in men, there was a nonsignificant positive trend for total fluid intake [> 1,500 vs. ≤ 1,000 ml/day: HR = 1.50, 95% CI = 0.95–2.37, P trend = 0.08) and a significant positive trend for coffee intake (> 6 vs. ≤ 2 cups/day: HR = 1.60, 95% CI = 0.96–2.66, P trend = 0.05). However, a nonsignificant positive trend for total fluid intake was no longer observed when additionally adjusting for coffee intake. Tests for interaction were not significant. In conclusion, total fluid intake was not associated with colorectal cancer risk in either men or women. There was no evidence that fiber intake modified associations. Of the specific beverages, coffee intake was positively associated with rectal cancer risk in men.

ACKNOWLEDGMENTS

This project was conducted within the Joint Research Program of the Dutch water companies by researchers from Maastricht University and Kiwa Water Research. External review of the design and results was conducted by a Scientific Advisory Committee consisting of P. Hunter (University of East Anglia, Norwich, United Kingdom), R. Rylander (Sweden), and M. I. Sinclair (Water Quality Research Australia Limited, Monash University, Australia). The authors are much indebted for their valuable comments and would also like to thank Margreet Mons for initiating this project, involvement in the design and data collection, and advice. Furthermore, we are indebted to the participants of this study and wish to thank the Dutch Cancer Society for financial support, the cancer registries (IKA, IKL, IKMN, IKN, IKO, IKR, IKST, IKW, IKZ and VIKC), and the Netherlands nationwide registry of pathology (PALGA). We also thank A. Volovics and A. Kester for statistical advice; S. van de Crommert, H. Brants, J. Nelissen, C. de Zwart, M. Moll, W. van Dijk, and A. Pisters for assistance; and H. van Montfort, T. van Moergastel, L. van den Bosch, R. Schmeitz, and J. Berben for programming assistance. None of the authors had a financial or personal conflict of interest. Sources of funding were 1) KIWA Water Research and 2) Dutch Cancer Society.