Folic acid may reduce some childhood cancers
MedWire News: Rates of two childhood cancers that are thought to originate in utero have fallen significantly since the introduction of mandatory fortification of grain-enriched products with folic acid, US study data show.
In their analysis of population-based surveillance data, Amy Linabery (University of Minnesota, Minneapolis) and colleagues found that rates of Wilms tumor and primitive neuroectodermal tumors (PNETs) decreased following mandatory folic acid fortification.
The researchers explain that folate is critical for embryonic development because of its contributions to DNA biosynthesis, cell proliferation, and DNA methylation. Along with strong evidence to show that folic acid consumption significantly reduces the incidence of offspring neural tube defects, epidemiologic evidence indicates that prenatal vitamin supplementation also reduces the risk for some childhood cancers.
In 1992, the US Public Health Service recommended a minimum daily folic acid intake of 400 mg for women of child-bearing age. And in 1996 the US Food and Drug Administration mandated that all enriched grain products be fortified with folic acid by January 1, 1998.
An analysis of women aged 15 to 44 years showed a significant increase in mean serum folate concentrations between women tested in 1988 to 1991, and those tested in 1999 (6.3 vs 16.2 ng/mL).
In the present study, Linabery and team used Surveillance, Epidemiology, and End Results program data (1986‑2008), to calculate pre- versus postfortification cancer incidence rate ratios (IRRs) in children aged 0 to 4 years.
From 1986 through 2008, 8829 children aged 0 to 4 years were diagnosed with malignancies, including 3790 and 3299 estimated to have in utero origins during the pre- and postfortification periods, respectively.
As reported in Pediatrics, pre- and postfortification incidence rates were similar for all cancers combined (IRR=1.01) and for most specific cancer types.
However, rates of Wilms tumor, PNETs, and ependymomas were significantly lower postfortification, with respective IRRs of 0.80, 0.56, and 0.70. These three cancers are all thought to have prenatal origins, the researchers note.
Regression models detected increasing Wilms tumor incidence from 1986 through 1997 (annual percent change [APC]=2.2%) followed by a sizable decline from 1997 through 2008 (APC=−4.0%).
PNET incidence also increased from 1986 through 1993 (APC=11.5%) followed by a sharp decrease from 1993 through 2008 (APC=−7.4%). There was no inflection point in the ependymoma trend, but a significant decrease in annual incidence was detected from 1986 to 2008 (APC=−2.7%).
Linabery and co-authors point out that the reversal in the incidence trend for Wilms tumor coincided with the introduction of mandatory fortification of grain products with folic acid, while the reversal in the PNET trend may reflect the recommendation of a minimum daily folic acid intake of 400 mg for women of child-bearing age.
The findings correspond with those observed in a smaller study conducted in Canada, but further research is needed to confirm the findings, rule out other explanations, and elucidate the mechanisms by which folic acid reduce the incidence of these cancers, the team concludes.
By Laura Cowen