Integrated surveillance strategy to support the prevention of neural tube defects through food fortification with folic acid: the experience of Costa Rica

Abstract

Purpose: (1) To describe how Costa Rica implemented an integrated surveillance strategy of folate deficiency, neural tube defects (NTDs) prevalence, NTDs-associated infant mortality rate (NTDs-IMR), and folic acid food fortification (FAFF), to support with evidence NTDs prevention policies; (2) to disseminate updated data from monitoring programs. Methods: We performed a cross-sectional analysis, using the databases of national surveillance systems for NTDs outcomes to compare NTDs-prevalence and NTDs-IMR observed in the pre-fortification (1987–1998) and post-fortification (2010–2020) periods. In addition, using data from FAFF monitoring program (2010–2020), means of folic acid concentration (mg/kg) and folic acid daily intake (μg/day) were calculated for each fortified food (corn and wheat flour, rice and milk), as well as its contribution to folic acid estimated average requirement (EAR). Results: After FAFF Costa Rica showed a decrease of 84% in folic acid deficiency in women of childbearing age, as well as a 53% decrease in the prevalence of NTDs, falling from 11.82/10,000 to 5.52/10,000 livebirths. In addition, there was a 76% reduction in the NTDs-IMR from 77.01/100,000 to 18.66/100,000 livebirths. Between 2010 and 2020, all fortified foods provided an average contribution of 119% of the EAR of folic acid in the population. Conclusion: To reduce NTD risk, an integrated surveillance strategy is essential not only to base prevention strategies on evidence, but also to demonstrate their impact and improve interventions over time. The experience in Costa Rica provides evidence that this type of surveillance is feasible to be implemented in developing countries.