Folic Acid Associated with Reduced Risk
Reference: Advance for Speech-Language Pathologists Audiologists (Nov. 4, 2011)
The use of folic acid supplements by women during the periconceptional period has been found to be associated with a reduced risk of children having severe language delay at age 3, according to a Norwegian study.
Randomized controlled trials and other studies have demonstrated that folic acid supplements taken during the period from four weeks before conception to eight weeks afterward reduce the risk of neural tube defects. “To our knowledge none of the trials have followed up their sample to investigate whether these supplements have effects on neurodevelopment that are only manifest after birth,” the researchers reported.
The new study was conducted by Christine Roth, ClinPsyD, MSc, of the Norwegian Institute of Public Health, in Oslo, and colleagues. They investigated whether maternal use of folic acid supplements was associated with a reduced risk of severe language delay among offspring at age 3.
“Unlike the United States, Norway does not forify foods with folic acid, increasing the contrast in relative folate status between women who do and do not take folic acid supplements,” the researchers noted.
Pregnant women in Norway were recruited for the study beginning in 1999. Data were included on children born before 2008 whose mothers returned the three-year follow-up questionnaire by June 16, 2010. Maternal use of folic acid supplements within the interval between four weeks before and eight weeks after conception was the exposure.
The primary outcome measured for the study was children’s language competency at age 3 as gauged by maternal report on a six-point ordinal language grammar scale. Children with minimal expressive language (only one-word or unintelligible utterances) were rated as having severe language delay.
The main analysis for the study involved 38,954 children: 19,956 boys and 18,998 girls. A total of 204 (0.5 percent) of the children (159 boys and 45 girls) were rated as having severe language delay. Children whose mothers took no dietary supplements in the specified exposure interval comprised the control group. there were 9,052 children in this group, including 81 (0.9 percent) with severe language delay.
The researchers reported the data for three patterns of exposure to maternal dietary supplements: 1) other supplements, but no folic acid 2) folic acid only; and 3) folic acid in combination with other supplements.
The first group numbered 2,480 children, including 22 (0.9 percent), with severe language delay. The second group, of folic acid only, had 7,127 children, 28 (0.4 percent) of whom had severe language delay. The last group was comprised of 19,005 children, including 73 (0.4 percent) with severe language delay.
Maternal use of supplements containing folic acid within the periconceptional period was associated with a substantially reduced risk of severe language delay in children at age 3, the researchers discovered.
“We found no association, however, between maternal use of folic acid supplements and significant delay in gross motor skills at age 3,” they reported. “The specificity provides some reassurance that there is no confounding by an unmeasured factor. Such a factor might be expected to relate to both language and motor delay.”
No previous prospective observational study examined the relation of prenatal folic acid supplements to severe language delay in children.
“If this relationship were shown to be causal in future research, it would have important implications for understanding the biological processes underlying disrupted neurodevelopment, for the prevention of neurodevelopmental disorders, and for policies of folic acid supplementation for women of reproductive age,” the investigators said.
Reference: Roth, C., Magnus, P., Schjolberg, S. et al. (2011). Folic acid supplements in pregnancy and severe language delay in children. JAMA, 306 (14): 1566-73