叶酸食品营养强化降低先天性心脏病发病率
2016年8月30日，美国心脏学会官方期刊《循环》正式发表加拿大公共卫生局慢性疾病预防中心、不列颠哥伦比亚妇幼医院、不列颠哥伦比亚大学、戴尔豪斯大学、曼尼托巴大学、渥太华大学、卡尔加里大学、麦吉尔大学的人群队列研究报告，发现在人类饮食中添加叶酸可以降低先天性心脏病的发生率。
该研究对1990～2011年59万位加拿大孕妇进行分析，排除了孕妇年龄、多胎（双胞胎、三胞胎）、妊娠并发症、终止妊娠、产前诊断等影响因素之后，发现叶酸强化食品与所有非染色体心脏缺陷减少11%有相关性（P=0.031）。
叶酸对一些特定类型的先天性心脏病作用更显著，如圆锥动脉干畸形减少27%（P=0.0002）、主动脉缩窄减少23%（P=0.022）、室间隔缺损减少15%（P=0.013）、房间隔缺损减少18%（P=0.012）。对严重的非心脏圆锥动脉干缺陷（P=0.086）、其他心脏及循环系统异常（P=0.97）无显著影响。
从1998年开始加拿大强制在各类面粉和玉米粉中添加叶酸预防神经管缺陷。这项研究的结果也适用于美国人口，因为美国也在同一时期实行叶酸的食品营养强化。
叶酸对于快速细胞分裂和生长非常重要。叶酸缺乏可以引起神经管缺陷导致多种婴儿期并发症（如脊柱裂、脊柱和脊髓的异常）和贫血。备孕的妇女在怀孕之前应该开始服用叶酸补充剂。
Circulation. 2016 Aug 30;134(9):647-55.
Effect of Folic Acid Food Fortification in Canada on Congenital Heart Disease Subtypes.
Liu S, Joseph KS, Luo W, León JA, Lisonkova S, Van den Hof M, Evans J, Lim K, Little J, Sauve R, Kramer MS; Canadian Perinatal Surveillance System (Public Health Agency of Canada).
Centre for Chronic Disease Prevention, Public Health Agency of Canada, Ottawa, ON, Canada; Children's and Women's Hospital of British Columbia, Vancouver, BC, Canada; University of British Columbia, Vancouver, BC, Canada; Dalhousie University, NS, Canada; University of Manitoba, Winnipeg, MB, Canada; University of Ottawa, Ottawa, ON, Canada; University of Calgary, Calgary, AB, Canada; McGill University, Montreal, QC, Canada.
BACKGROUND: Previous studies have yielded inconsistent results for the effects of periconceptional multivitamins containing folic acid and of folic acid food fortification on congenital heart defects (CHDs).
METHODS: We carried out a population-based cohort study (N=5,901,701) of all live births and stillbirths (including late-pregnancy terminations) delivered at ≥20 weeks' gestation in Canada (except Québec and Manitoba) from 1990 to 2011. CHD cases were diagnosed at birth and in infancy (n=72,591). We compared prevalence rates and temporal trends in CHD subtypes before and after 1998 (the year that fortification was mandated). An ecological study based on 22 calendar years, 14 geographic areas, and Poisson regression analysis was used to quantify the effect of folic acid food fortification on nonchromosomal CHD subtypes (n=66,980) after controlling for changes in maternal age, prepregnancy diabetes mellitus, preterm preeclampsia, multiple birth, and termination of pregnancy.
RESULTS: The overall birth prevalence rate of CHDs was 12.3 per 1000 total births. Rates of most CHD subtypes decreased between 1990 and 2011 except for atrial septal defects, which increased significantly. Folic acid food fortification was associated with lower rates of conotruncal defects (adjusted rate ratio [aRR], 0.73, 95% confidence interval [CI], 0.62-0.85), coarctation of the aorta (aRR, 0.77; 95% CI, 0.61-0.96), ventricular septal defects (aRR, 0.85; 95% CI, 0.75-0.96), and atrial septal defects (aRR, 0.82; 95% CI, 0.69-0.95) but not severe nonconotruncal heart defects (aRR, 0.81; 95% CI, 0.65-1.03) and other heart or circulatory system abnormalities (aRR, 0.98; 95% CI, 0.89-1.11).
CONCLUSIONS: The association between food fortification with folic acid and a reduction in the birth prevalence of specific CHDs provides modest evidence for additional benefit from this intervention.
KEYWORDS: association; folic acid; heart defects, congenital; primary prevention
PMID: 27572879
PMCID: PMC4998126
DOI: 10.1161/CIRCULATIONAHA.116.022126