Neural tube defects prevalence does not increase aftermodification of the folic acid fortification program in Chile

Abstract

Background:In 2000, Chile’s Ministry of Health mandated fortification ofwheat flour with folic acid at a concentration of 2.2 mg/kg to prevent neuraltube defects (NTDs), resulting in a 50% reduction in NTD prevalence. Con-cerns about possible collateral effects of high folic acid intake led, in 2009, todecrease the folic acid fortification to 1.8 mg/kg of flour. Our study evaluatedthe impact of this modification on the prevalence of NTDs in Santiago.Methods:This study measured the prevalence of NTDs in live births and still-births born in Santiago. We calculated prevalence ratios (PR) and 95% confi-dence intervals (CI) between pre-folic acid fortification (1999–2000), post-folicacid fortification (2001–2009), and post-modified folic acid fortification (2010–2015) periods for all NTDs and their specific types. We used chi-square tests toanalyze proportions, and a Joinpoint regression to visualize prevalence timetrends.Results:The NTD prevalence for the period 2001–2015 was 8.9 per 10,000births, which represents a 48% reduction (PR=0.52; 95% CI=0.45–0.61;p< .001) from the pre-folic acid fortification period. During 2010–2015, theNTD prevalence was 9.5/10,000 births, which was higher, but not statisticallysignificantly different from 2001 to 2009 prevalence of 8.6/10,000 (PR=1.11;95% CI=0.96–1.30,p=.17).Conclusions:Decreasing the concentration of folic acid fortification was notassociated with a statistically significant change in the prevalence of NTDs.Mandatory folic acid fortification continues to be a safe and highly effectivepolicy to prevent NTDs. Future studies should evaluate the prevalence ofNTDs across Chile and adherence to folic acid fortification mandates