Folic acid fortification of grain products “significantly decreases the prevalence of spina bifida and anencephaly among non-Hispanic whites and Hispanics,” according to Sonja A. Rasmussen, MD, one of the authors of a CDC study of US rates of spina bifida and anencephaly by race/ethnicity from 1995 to 2002. Folic acid fortification was also associated with a nonsignificant decline in neural tube defects among non-Hispanic blacks, added Dr. Rasmussen, a Clinical Geneticist in the CDC’s National Center on Birth Defects and Developmental Disabilities in Atlanta. The study findings were published in the September Pediatrics.

BIRTH DEFECT DATA

Trends in the prevalence of spina bifida and anencephaly were examined with data from the birth defect surveillance systems in 21 states, Dr. Rasmussen said. During the study period, these data revealed 4,468 spina bifida and 2,625 anencephaly cases out of about 11.1 million births (1.7 million among non-Hispanic blacks, 2.7 million among Hispanics, and 6.7 million among non-Hispanic whites).

Folic acid fortification of grain products in the United States began in an optional capacity in January 1997 and became mandatory in October 1998, Dr. Rasmussen noted. In the two years of the study when there was no folate fortification, spina bifida prevalence was 6.49 per 10,000 births for Hispanics, 5.13 per 10,000 for non-Hispanic whites, and 3.57 per 10,000 for non-Hispanic blacks. Those rates declined to 4.18, 3.37, and 2.9 per 10,000, respectively, during the optional fortification period and to 0.64, 0.66, and 0.81 per 10,000, respectively, after folate fortification became mandatory, she reported.

Anencephaly prevalence during the prefortification period was 3.85 per 10,000 births for Hispanics, 2.79 per 10,000 for non-Hispanic whites, and 1.98 per 10,000 for non-Hispanic blacks. Those rates were 3.55, 2.12, and 1.82 per 10,000, respectively, during the optional fortification period and 0.74, 0.71, and 0.91 per 10,000, respectively, during the mandatory fortification period. For non-Hispanic blacks, the decline in spina bifida was of borderline significance and the drop in anencephaly was nonsignificant.

LOWER RISK NOT LOW ENOUGH

The reasons for the differing risk of neural tube defects between racial/ethnic groups are unknown, the authors related. “However, it is likely that a combination of genetic and environmental factors is responsible,” they said.

Until such time as an answer is found, it is important for clinicians to continue to recommend that all women of childbearing age get 400 μg of folic acid per day, whether it be through a multivitamin, folic acid supplement, or breakfast cereal containing 100% of the daily value of folic acid, Dr. Rasmussen stressed. “Even though our study showed a substantial decrease in neural tube defects as a result of folic acid fortification, the rates were still higher than what we would anticipate if we had gotten a full impact of folic acid,” she pointed out.

PUBLIC POLICY

In the US, there are still an estimated 2,000 folic acid–preventable spina bifidas and anencephalies annually, Robert L. Brent, MD, PhD, and Godfrey P. Oakley, Jr, MD, reported in an editorial criticizing efforts here and abroad to prevent spina bifida and anencephaly by fortifying grain products with folic acid. “We know why folic acid–preventable birth defects continue to occur unnecessarily and tragically in the US,” they said. “Our government failed to take the steps needed to assure that not a single child is affected with folic acid–preventable spina bifida and anencephaly. The FDA did not require a high enough concentration of folic acid in ‘enriched’ grain products.”

Indeed, although it is recommended that women of childbearing age consume 400 μg of synthetic folic acid daily to prevent spina bifida and anencephaly in their offspring, the FDA required a fortification level that would provide only 100 μg daily.

Worldwide, about 200,000 children are born with folic acid– preventable spina bifida or anencephaly each year, Drs. Brent and Oakley added. “It is a tragic failure of public policy, both in the United States and around the world, that a single case of folic acid–preventable spina bifida and anencephaly occurs,” they maintained.

The two physicians urged the FDA to use its emergency powers to immediately require at least double the amount of folic acid currently added to grain products. They also recommended that the FDA move quickly to require the addition of enough vitamin B₁₂ to those products to provide at least 2.4 μg daily, noting that maternal B₁₂ deficiency during pregnancy has also been associated with neural tube defects such as spina bifida.

Dr. Brent is the Distinguished Professor of Pediatrics, Radiology, and Pathology at Thomas Jefferson University in Wilmington, Delaware. Dr. Oakley is Research Professor of Epidemiology at the Rollins School of Public Health of Emory University in Atlanta.

NR

—Jean McCann

Suggested Reading
Brent RL, Oakley GP Jr. The FDA must require the addition of more folic acid in “enriched” flour and other grains. Pediatrics. 2005;116:753-755.
Williams LJ, Rasmussen SA, Flores A, et al. Decline in the prevalence of spina bifida and anencephaly by race/ethnicity: 1995-2002. Pediatrics. 2005;116:580-586.

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