Reduction in orofacial clefts following folic acid fortification of the U.S. grain supply

Authors

  • Mahsa M. Yazdy,

    Corresponding author
    1. National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
    2. Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee
    • National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
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  • Margaret A. Honein,

    1. National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
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  • Jian Xing

    1. National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
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  • This article is a US Government work and, as such, is in the public domain in the United States of America.Presented as a poster at the 2006 Congress of Epidemiology, a joint meeting of the American College of Epidemiology, Epidemiology Section of the American Public Health Association, and the Society for Epidemiologic Research, June 21–24, 2006, in Seattle, Washington.Presented as a poster at the 9th annual meeting of the National Birth Defects Prevention Network, January 30–February 1, 2006, in Arlington, Virginia.The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention/the Agency for Toxic Substances and Disease Registry.

Abstract

BACKGROUND:

Folic acid fortification in the United States became mandatory January 1, 1998, to reduce the occurrence of neural tube defects (NTDs). We evaluated the impact of folic acid fortification on orofacial clefts using United States birth certificate data for 45 states and the District of Columbia.

METHODS:

Prevalence ratios (PRs) were calculated comparing orofacial cleft prevalence among births prefortification (1/1990–12/1996) and postfortification (10/1998–12/2002), based on fortification status at conception. The JoinPoint Regression Program and exponentially weighted moving average charts (EWMA) were used to assess the timing of any statistically significant changes in prevalence. Data were stratified by maternal race/ethnicity, age, smoking, and timing of prenatal care.

RESULTS:

Orofacial clefts declined following folic acid fortification (PR = 0.94; 95% CI: 0.92–0.96). The EWMA chart flagged a significant decrease in the fourth quarter of 1998. The JoinPoint graph had one change in slope, with a significant quarterly percent change (−0.34) between 1996 and 2002. The decline in orofacial clefts occurred in non-Hispanic Whites but not other racial/ethnic groups, nonsmokers but not women who reported smoking during pregnancy, and women who received prenatal care in the first trimester but not women who began receiving care later in pregnancy.

CONCLUSION:

Folic acid fortification in the United States was associated with a small decrease in orofacial cleft prevalence, with the timing of the decline consistent with the introduction of fortification. The decline is much smaller than that observed for NTDs, but nonetheless suggests an additional benefit of this public health intervention. Birth Defects Research (Part A) © 2006 Wiley-Liss, Inc.

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