Breast Cancer Incidence: A Possible Relationship to Folic Acid Fortification?
P Reddy, M Hogarth, C-S Li, JW Miller, R Green. University of California, Davis, Sacramento, CA
Background: In 1998 the U.S. food supply was fortified with folic acid. This was successful in reducing both the incidence of neural tube defects and the prevalence of folate deficiency. Fortification has, however, led to excess folate consumption by a significant percentage of the population. Regarding cancer, excess folate may prevent tumor initiation by maintenance of DNA integrity. Conversely, folate may promote progression of established cancers by providing a nutrient that is rate limiting for proliferating cell clones. Folate plays a key role in methylation and may influence cancer development and progression through epigenetic mechanisms. We studied effects of folic acid fortification by comparing breast cancer incidence rates in the U.S. before and after folic acid fortification with the rates in the U.K., there is no folic acid fortification.
Design: Breast cancer incidence trends from 1985-2004 were analyzed. U.S. data for breast cancer incidence was derived from the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) registry. The U.K data for breast cancer incidence was derived directly from Cancer Research UK.
Results: There was a statistically significant increase in breast cancer incidence in both the U.S. and U.K. over time during the period 1985 1998.
After 1998, breast cancer incidence decreased significantly in the U.S. compared with the UK, where breast cancer incidence has been increasing, though not significantly.
The decline in the U.S. coincides temporally with the introduction of folic acid fortification.
Conclusions: The epidemiological evidence of decreasing breast cancer incidence in the U.S. is remarkable. Temporal relationships are consistent with a possible influence of folic acid fortification on breast cancer incidence in the U.S.
Monday, March 9, 2009 9:30 AM
Poster Session I Stowell-Orbison/Autopsy Award # 44, Monday Morning