The incidence of neural tube defects in the United States has declined by almost 20% since the mandatory addition of folic acid to bread and pasta in 1998. The results have renewed pressure on the UK government to implement a similar policy.
Margaret Honein and colleagues from the National Center on Birth Defects and Developmental Disabilities in Atlanta, Georgia, studied birth certificate data in the years before and after the Food and Drug Administration ruled that all grain products should be fortified with folic acid (JAMA 2001;285:2981-6).
The number of neural tube defects that were reported on birth certificates fell from 37.8 per 100000 live births before fortification to 30.5 per 100000 live births after fortification, representing a 19% decline.
The prevalence of spina bifida fell by 23% from 26.2 per 100000 births to 20.2 per 100000 births. Anencephaly decreased by 11% from 11.6 per 100000 births to 10.3 per 100000 births. Among women who received only third trimester care or no prenatal care the prevalence of neural tube defects declined by 13% This implies that the decline was due to the fortification policy rather than an increased uptake of folic acid supplements.
In an accompanying editorial (JAMA 2001;285:3022-3) James Mills and Lucinda England of the paediatric epidemiology section at the National Institutes of Health in Bethesda, Maryland, caution that these figures may be imprecise because birth certificate data do not include fetal deaths or babies who are stillborn and because many birth defects go unrecorded on certificates. In addition, many fetuses with neural tube defects are identified during pregnancy and lead to a termination.
It is a year and a half since the Committee on Medical Aspects of Food and Nutrition Policy (COMA), an influential government advisory committee, recommended that the United Kingdom should fortify all flour with folic acid. Consultation on the committee's report ended in October last year, and since then nothing has been heard.
Nick Wald, a member of the committee and professor of environmental and preventive medicine at the Wolfson Institute of Preventive Medicine in London, said: “All the relevant committees have recommended that the UK should fortify flour with folic acid. I don't know why there is a delay in implementing such a policy.”
A spokesman for the Department of Health said: “We are still waiting a final decision from the health minister.”
The COMA report concluded that 240 mg of folic acid should be added to every 100 g of flour to reduce the incidence of neural tube defects by 41% This is a higher level of fortification than in the United States, where 140 mg of folic acid is added to every 100 g of grain.
Tony Britton, spokesman for the Association for Spina Bifida and Hydrocephalus, said: “We could expect a much larger reduction in the prevalence of neural tube defects than was seen in the US if we implement COMA's recommended levels.”
Professor Wald said he thought that 240 mg was probably still too low. “I think it is probably too conservative, but if we start with a relatively modest amount we can then review the level at a later stage.”
He said that the current policy of advising women to take folic acid supplements was not working. “The main problem is that women just don't take it at the right time. Half, or more, pregnancies are unplanned, so women won't have been protected at the crucial time.”
Figure.
BIOPHOTO ASSOCIATES/SPL
The back of a spina bifida baby after surgery