Changes in Frequencies of Select Congenital Anomalies since the Onset of Folic Acid Fortification in a Canadian Birth Defect Registry

Abstract

Objectives: Fortification of grain products with folic acid has been shown to significantly reduce the occurrence of neural tube defects (NTDs) in Canada and elsewhere. However, the impact on non-NTD anomalies has not been well studied.Methods: Using the Alberta Congenital Anomalies Surveillance System (ACASS), we examined changes in occurrence of select congenital anomalies where folic acid supplementation with multivitamins had previously been suggested to have an effect. Anomalies documented in the ACASS 1992-1996 (pre-fortification) were compared to 1999-2003 (post-fortification).Results: A significant decrease in spina bifida (OR 0.51, 95% CI 0.36-0.73) and ostium secundum atrial septal defects (OR 0.80, 95% CI 0.69-0.93) was evident, but there was a significant increase in obstructive defects of the renal pelvis and ureter (OR 1.45, 95% CI 1.24-1.70), abdominal wall defects (OR 1.40, 95% CI 1.04-1.88) and pyloric stenosis (OR 1.49, 95% CI 1.18-1.89). Conclusions:Consistent with other studies, a 50% reduction in spina bifida was associated with the post-fortification time period. Supporting the possibility that folic acid fortification may play a role in preventing other birth defects, a 20% reduction in atrial septal defects was also associated. The increase in abdominal wall defects, most notably gastroschisis, is likely related to pre-existing increasing trends documented in several regions around the world. The increase in pyloric stenosis and obstructive urinary tract defects was not expected and any causal relationship with folic acid fortification remains unclear. Similar studies by other birth defects surveillance systems in Canada and elsewhere are needed to confirm these trends.

Biomarkers of Nutrition for Development—Folate Review

“…The question of whether birth abnormalities other than NTDs are significantly affected by maternal folic acid intake has been investigated (109)(110)(111)(112)(113). There is, however, a lack of consistent evidence that the risk of birth defects other than NTDs is positively affected by folic acid in the amount consumed in supplements and/or fortified foods (109)(110)(111)(112)(113).…”

“…There is, however, a lack of consistent evidence that the risk of birth defects other than NTDs is positively affected by folic acid in the amount consumed in supplements and/or fortified foods (109)(110)(111)(112)(113). · Few nationally representative studies were available for investigation; but, on the basis of evidence from countries with such survey data, deficient folate status (i.e., .5% of the population with a serum folate value below the normal range) was identified in specific age groups in 6 of 8 countries, most notably in preschool-aged children in Venezuela, pregnant women in Costa Rica (before mandatory fortification) and Venezuela, and the elderly in the United Kingdom.…”

Environmental exposures and development

“…Initial work in experimental embryology and developmental biology used single agents to disrupt developmental processes, demonstrating vulnerability to a range of exposures (10). As our understanding of developmental biology and toxicology improved it was recognized that interactions between exposures and maternal/paternal health or fetal/placental genetic constitution could play a role (23, 26). While much still remains to be understood, current data suggests that developmental abnormalities are predominantly the result of biological-environmental interactions (27, 28).…”

Folic acid fortification and the birth prevalence of congenital heart defect cases in Alberta, Canada

“…The impact of FAF on other congenital anomalies, including CHDs, has also been assessed. The results are not as definitive (Simmons et al, ; Canfield et al, 2005; Robbins et al, ; Botto et al, ; Godwin et al, ; López‐Camelo et al, ).…”