|EVIDENCE-BASED MEDICINE: SUMMARY OF STUDY
|Year : 2016 | Volume
| Issue : 4 | Page : 125
Folic acid food fortification and congenital heart disease
Ajay Kumar Mishra
Department of General Medicine, CMC, Vellore, India
|Date of Web Publication||22-Nov-2016|
Source of Support: Shiliang Liu, K. S. Joseph, Wei Luo, Juan Andrés León, Sarka Lisonkova, Michiel Van den Hof, Jane Evans, Ken Lim, Julian Little, Reg Sauve and Michael S. Kramer and For the Canadian Perinatal Surveillance System (Public Health Agency of Canada). Effect of Folic Acid Food Fortification in Canada on Congenital Heart Disease Subtypes. Circulation 2016;134:647-655., Conflict of Interest: None
|How to cite this article:|
Mishra AK. Folic acid food fortification and congenital heart disease. Curr Med Issues 2016;14:125
Clinical Question: Does folic acid supplementation by fortification of food help prevent congenital heart disease in newborns?
Authors′ conclusion: Folic acid food supplementation through fortification of food is associated with lower rates of congenital heart disease (except severe nonconotruncal heart defects) and other heart or circulatory system abnormalities in newborns.
| Introduction|| |
The role of folic acid supplementation in pregnancy to prevent neural tube defects is well established. This has led to fortification of food with folic acid over more than two decades in countries like Canada. The role of this supplementation in preventing congenital heart defects (CHD), however, is not clear, and studies have shown inconsistent results. This study aimed to substantiate the role of periconceptional folic acid supplementation of folic acid in preventing CHD.
| Methodology|| |
In the year of 1998, folic acid fortification of food became a legal mandate in Canada. This ecological study compared the prevalence and trends of CHD before and after 1998. This population-based cohort included around 6 million live births and stillbirths from 14 geographic areas in Canada over a span of 22 years (1990-2011). Births from January 1999 on were considered exposed to this intervention. The effect of folate fortification on six subtypes of CHD was analyzed after controlling multiple confounders such as maternal age, gestational diabetes mellitus, and preeclampsia. The subtypes of CHD studied were CHD (1) conotruncal defects consisting of common truncus, transposition of great vessels, and tetralogy of Fallot; (2) nonconotruncal defects including endocardial cushion defects, common ventricle, and hypoplastic left heart syndrome; (3) coarctation of the aorta; (4) ventricular septal defect; (5) atrial septal defect, and (6) other heart and circulatory system anomalies.
| Results|| |
- Over 22 years, 5901,701 total births were recorded. Of these, 72,591 were diagnosed to have CHD. The prevalence rate of CHD in this population was 12.3/1000 births. Twenty percent of the above were severe CHD (first three subtypes of CHD mentioned above)
- Over the years, there was a gradual reduction of CHD
- After adjustment for confounding factors, folic acid food fortification was associated with a 27% reduction in conotruncal defects, a 23% reduction in coarctation of the aorta, a 15% reduction in ventricular septal defects, and an 18% reduction in atrial septal defects
- These effects were not seen in patients with not severe nonconotruncal CHD and other anomalies of the heart and circulatory system.
Infant and maternal methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism can be contributory to CHD. Periconceptional supplementation of folic acid reduces MTHFR C677T-related polymorphism thus preventing CHD.
| Conclusions|| |
- This large-scale ecological study gives modest evidence in the support of efficacy of folic acid supplementation for decreasing CHD
- The impact of known confounders (other nutrient supplements, smoking, obesity, diet, and lifestyle) and unknown confounders toward the outcome of declining CHD is undisputable. Yet most of these confounders may have a negative association thus requiring prevention or management
- In the presence of strong evidence of reduction in various congenital defects, physicians and obstetricians need to be aware of this double-edged benefit of folic acid. These warrants appropriate administrative action for achieving fortification of food in the developing countries as well.