Prevalence of severe congenital heart disease after folic acid fortification of grain products: time trend analysis in Quebec, CanadaBMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b1673 (Published 13 May 2009) Cite this as: BMJ 2009;338:b1673
- Raluca Ionescu-Ittu, PhD candidate1,
- Ariane J Marelli, associate professor of medicine2, director3,
- Andrew S Mackie, assistant professor of paediatrics4,
- Louise Pilote, professor of medicine2, director5
- 1Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Canada
- 2McGill University, Montreal, Canada
- 3McGill Adult Unit for Congenital Heart Disease Excellence (MAUDE), McGill University Health Centre, Montreal, Canada
- 4University of Alberta, Division of Cardiology, Stollery Children’s Hospital, Edmonton, Canada
- 5Division of General Internal Medicine, McGill University Health Centre, Montreal, Canada
- Correspondence to: L Pilote, Royal Victoria Hospital, V Building, 687 Pine Avenue West, Room V2.17, Montreal, QC, Canada H3A 1A1
- Accepted 28 January 2009
Objective To investigate whether the 1998 government policy for mandatory fortification of flour and pasta products with folate was followed by a reduction in the prevalence of severe congenital heart defects.
Design Time trend analysis.
Setting Province of Quebec, Canada.
Participants Infants born in 1990-2005 identified with severe congenital heart defects (tetralogy of Fallot, endocardial cushion defects, univentricular hearts, truncus arteriosus, or transposition complexes) in Quebec administrative databases.
Methods Data analysed in two time periods (before and after fortification). Birth prevalence measured annually as infants (live and stillbirths) with severe congenital heart defects per 1000 births in Quebec. Changes in the birth prevalence from the period before to the period after fortification were estimated with Poisson regression.
Results Among the 1 324 440 births in Quebec in 1990-2005 there were 2083 infants born with severe congenital heart defects, corresponding to an average birth prevalence of 1.57/1000 births. Time trend analysis showed no change in the birth prevalence of severe birth defects in the nine years before fortification (rate ratio 1.01, 95% confidence interval 0.99 to 1.03), while in the seven years after fortification there was a significant 6% decrease per year (0.94, 0.90 to 0.97).
Conclusions Public health measures to increase folic acid intake were followed by a decrease in the birth prevalence of severe congenital heart defects. These findings support the hypothesis that folic acid has a preventive effect on heart defects.
Contributors: RI-I contributed to the conception and design of the study, analysed the data, interpreted the results, and drafted the manuscript. AJM and ASM acquired the data, interpreted the results, and critically revised the manuscript. LP acquired the data, contributed to the conception and design of the study, interpreted the results, and critically revised the manuscript. LP is guarantor.
Funding: AJM was funded by the Heart and Stroke Foundation of Canada. ASM is funded by the Fonds de Recherche en Santé du Québec (FRSQ). LP is a senior investigator funded by the FRSQ and James McGill professor of Medicine. The study was funded in part by the Heart and Stroke foundation of Canada and by the FRSQ.
Competing interests: None declared.
Ethical approval: This study was approved by Quebec Commission for Access to Information, the McGill University Health Center ethics board, and the Quebec Statistics Institute. The study is based on administrative databases and subjects were not identifiable to the authors.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.