Serum Folate and Cancer Mortality Among U.S. Adults: Findings from the Third National Health and Nutritional Examination Survey Linked Mortality File
- 1National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, and 2Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia; and 3Department of Medical Genetics, University of British Columbia, Vancouver, Canada
- Requests for reprints:
Quanhe Yang, Office of Public Health Genomics, Centers for Disease Control and Prevention (CDC), 1600 Clitton Road, Mail Stop E-bl, Atlanta, GA 30333. Phone: 404-498-0067; Fax: 404-498-0150. E-mail: qay0{at}cdc.gov
Abstract
Background: The relation between folate status and cancer is controversial. Several epidemiologic studies have suggested that increased folate intake is associated with reduced risk of various cancers, others have found no such associations, and a few have suggested that high folate intake might increase the risk of certain cancers.
Methods: Using data from the Third National Health and Nutrition Examination Survey (NHANES III) Mortality File, a prospective cohort study of a nationally representative sample of 14,611 U.S. adults, we conducted Cox proportional hazards regression modeling to investigate the association of baseline serum folate concentrations and all-cancer mortality determined from linked death certificate data.
Results: Relative to the lowest quintile of serum folate (<3.0 ng/mL), the multivariable-adjusted hazard ratios across quintiles 2 to 5 were: 1.61 [95% confidence interval (95% CI), 1.11-2.32], 1.00 (95% CI, 0.65-1.49), 1.39 (95% CI, 0.96-2.03), and 0.85 (95% CI, 0.59-1.22). These findings did not differ substantially by age or sex, but the higher risk for those in the second quintile appeared limited to non-Hispanic whites.
Conclusion: These findings suggest that there may be a nonlinear relationship between folate status and the risk of all-cancer mortality such that persons with low, but not grossly deficient, serum blood folate concentrations may be at increased risk. Further study is needed to determine whether these findings are due to chance, and if not, to clarify their biological basis. (Cancer Epidemiol Biomarkers Prev 2009;18(5):1439–47)
Footnotes
-
Author contributions: Quanhe Yang had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Quanhe Yang, Roberd M. Bostick, W. Dana Flanders. Analysis and interpretation of the data: Quanhe Yang, Roberd M. Bostick, J.M. Friedman, W. Dana Flanders. Drafting of the manuscript: Quanhe Yang. Critical revision of the manuscript for important intellectual content: Quanhe Yang, Roberd M. Bostick, J.M. Friedman, W. Dana Flanders. Statistical expertise: Quanhe Yang and W. Dana Flanders.
-
Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.
-
- Accepted March 9, 2009.
- Received September 26, 2008.
- Revision received February 6, 2009.
