Multivitamin supplementation during pregnancy may be inversely associated with autism spectrum disorder (ASD) as well as intellectual disability in offspring, according to a study published in the BMJ.
Elizabeth A DeVilbiss, MA, LCPC, from the Dornsife School of Public Health at Drexel University in Philadelphia, and colleagues conducted an observational prospective cohort study of children living in Stockholm County, Sweden, for at least 4 years between 2001 and 2011. The cohort was restricted to children aged 4 to 15 years at the end of follow-up on December 31, 2011. Children were excluded if they were not in the medical birth register, not linked to birth mother, adopted, or had missing data on family disposable income or maternal age.
Data on ASD were taken from computerized registers covering all pathways of ASD diagnosis and care in Stockholm County. The multivitamins category included women who noted use of any multivitamin, regardless of combined use with additional iron or folic acid, or both. The main outcome measures were ASD with intellectual disability, ASD without intellectual disability, and any ASD.
A total of 273,107 mother–child pairs were identified and categorized into groups: multivitamins (62,840; 23.0%), iron only (90,138; 33.0%), iron and folic acid (25,445; 9.3%), folic acid only (2789; 1.0%), and none of the above (91,895; 33.7%). Regression analysis indicated that multivitamin use was associated with a lower likelihood of ASD with intellectual disability compared with nonuse of multivitamins, iron, and folic acid in all analyses (odds ratio [OR], 0.69). Multivitamin use was not associated with ASD without intellectual disability in any analysis.
The researchers found a suggestion of an increased association between folic acid use and ASD without intellectual disability in the multivariable regression (OR, 1.29). Iron use was not associated with ASD with or without intellectual disability in any analysis.
“We could not rule out the possibility that multivitamin supplementation may be inversely associated with ASD with intellectual disability,” the authors concluded. “Evidence that either iron or folic acid use were inversely associated with ASD was inconsistent.”
DeVilbiss EA, Magnusson C, Gardner RM, et al. Antenatal nutritional supplementation and autism spectrum disorders in the Stockholm youth cohort: population based cohort study [published online 4 Oct 2017]. BMJ. doi: 10.1136/bmj.j4273