Associations of Whole and Refined Grain Intakes with Adiposity-Related Cancer Risk in the Framingham Offspring Cohort (1991–2013)

ABSTRACT

Case-control studies suggest that higher whole grain and lower refined grain intakes are associated with reduced cancer risk, but longitudinal evidence is limited. The objective of this prospective cohort study is to evaluate associations between whole and refined grains and their food sources in relation to adiposity-related cancer risk. Participants were adults from the Framingham Offspring cohort (N = 3,184; ≥18 yr). Diet, measured using a food frequency questionnaire, medical and lifestyle data were collected at exam 5 (1991–95). Between 1991 and 2013, 565 adiposity-related cancers were ascertained using pathology reports. Cox proportional hazards models were used to estimate adjusted hazard ratios and 95% confidence intervals for associations of whole and refined grains with risk of adiposity-related cancers combined and with risk of breast and prostate cancers in exploratory site-specific analyses. Null associations between whole and refined grains and combined incidence of adiposity-related cancers were observed in multivariable-adjusted models (HR: 0.94; 95% CI: 0.71–1.23 and HR: 0.98; 95% CI: 0.70–1.38, respectively). In exploratory analyses, higher intakes of whole grains (oz eq/day) and whole grain food sources (servings/day) were associated with 39% and 47% lower breast cancer risk (HR: 0.61; 95% CI: 0.38–0.98 and HR: 0.53; 95% CI: 0.33–0.86, respectively). In conclusion, whole and refined grains were not associated with adiposity-related cancer risk. Whole grains may protect against breast cancer, but findings require confirmation within a larger sample and in other ethnic groups.

Conflict of Interest Statement

The authors declare that they have no conflict of interest.

Acknowledgments

This manuscript was not prepared in collaboration with the investigators of the FHS and does not necessarily reflect the opinions or views of the FHS, Boston University, or NHLBI.

Notes on Contributor

The authors' contributions are as follows: N.M. and N.P. conceived this project and developed the overall research plan. N.M. took the lead to write the paper and conducted the statistical analyses; Y.L. advised on the statistical analyses and reviewed the manuscript for the statistical accuracy of results. N.P., E.V.B., N.M.M., and R.B.H. provided insights into the review and revision of the manuscript for important intellectual content; N.P. had primary responsibility for the final content and for overseeing the entire study.

Additional information

Funding

The present study was supported by the American Cancer Society Research Scholar Grant (#RSG-12-005-01-CNE) awarded to N.P. The American Cancer Society had no role in the design and analysis of the study or in the writing of this article. The FHS is conducted and supported by the National Heart, Lung, and Blood Institute (NHLBI) in collaboration with Boston University (contract no. N01-HC-25195). Funding support for the Framingham FFQ datasets was provided by ARS Contract no. 53-3k06-5-10, ARS Agreement no. 58-1950-9-001, 58-1950-4-401 and 58-1950-7-707.