The Costa Rican experience: reduction of neural tube defects following food fortification programs.

Fortification of wheat flour in 1997 and corn flour in 1999 with folic acid among other micronutrients was implemented in Costa Rica by means of two decrees, resulting in an effective public health impact. A prevalence of 25% of folic acid serum levels deficiency detected in fertile women in 1996 decreased 87% in urban areas two years later, whereas in rural areas diminished by 63%. In addition, a significant reduction of neural tube defects at the national level has been reported, dropping from a rate of 9.7 per 1000 lb during the period 1996-1998 to 6.3 per 1000 lb in the period 1999-2000. Finally, there has been a reported 74% reduction in the number of Neural Tube Defects at Birth (NTB) at the National Children's Hospital, resulting in 105 cases treated in 1995 to 26 cases in 2001.