Effects of wheat flour fortification with folic acid on the prevalence of neural tube defects in Chile

Background: Congenital malformations (CMF) have an important role in infant mortality. Neural tube defects (NTD) have great relevance from both social and public health points of view. The ECLAMC (Collaborative Latin American Study of Congenital Malformations) maintains in Chile an epidemiological surveillance of CMF prevalence rate at birth since 1969. Aim: To assess the effect of wheat flour folic acid fortification on the prevalence of NTD. Patients and Methods: Only Anencephaly, Spina bifida and Cephalocele were considered as NTD. All children born in the maternities incorporated to ECLAMC between 1969 and 1999 were considered as belonging to the pre folic acid fortification period and those who were born from 2001 to 2010 were considered as belonging to the post fortification period. Results: The NTD prevalence rate at birth in the pre fortification period was 17.03/10,000. In the second period, there were 291,996 births and among them, 280 newborns were affected by a form of NTD (9.59 in 10,000 births). This represents a 44% decrease (p < 0.01). Anencephaly rate fell from 7.16/10,000 to 3.67/10,000, representing a 49% lower rate (p < 0.01). Spina bifida rate decreased from 8.61/10,000 to 4.49/10,000, representing a 48% lower rate (p < 0.01). Cephalocele had a 20% non-significant reduction. Conclusions: Wheat flour fortification with folic acid reduced by 44% the prevalence rate of NTD at birth. This means that NTDs were prevented in 185 Chilean newborns each year.