P1080 - Examining the Relationship Between Autism Spectrum Disorder and Neural Tube Defects

Background: Deficits in folate (vitamin B9) and cobalamin (vitamin B12) have been associated with adverse outcomes on the developing fetal nervous system. Folate deficiency poses a known increased risk of neural tube defects due to its integral part in nucleotide synthesis and methylation reactions in neural tube closure. Research also has linked low concentrations of cobalamin in amniotic fluid to neural tube defects. Existing research also suggests deficient levels of folate and cobalamin may be related to developmental delay and Autism Spectrum Disorder (ASD). However, an association between neural tube defects and ASD, which would support the association of folate and cobalamin deficiency with ASD, has not been reported.

Objective: We sought to explore the association between neural tube defects and ASD as a means to examine if there is support for the hypothesis that ASD is related to maternal folate and cobalamin deficiency during pregnancy.

Methods: A retrospective case control study was performed using the Military Health System Data Repository. Cases were identified by International Classification of Diseases, Ninth Revision (ICD-9) codes for ASD and were matched 3:1 with controls on sex, date of birth, and enrollment time frame. All included children were followed from birth until at least six months after their first ASD diagnosis; matched controls were followed for the same time period. ICD-9 codes identified NTDs in the healthcare records of children with autism and matched controls to determine if children with autism had an increased incidence of neural tube defects.

Results: A total of 8,760 children diagnosed with ASD between the ages of 2 and 18 years were matched with 26,280 controls. Cases and controls were 79.9% male, 7,762 (22.2%) had active duty mothers, the average age of ASD diagnosis was 4.1 years, and children with ASD had mothers who were slightly younger than mothers of children without ASD. The prevalence of NTDs was 0.17% in children without ASD and 0.73% in children with Autism. Children with autism were over 4 times (OR=4.46, 95% CI 2.90-6.26) as likely to have neural tube defects in our analysis.

Conclusions: In our analysis, odds of neural tube defects are over four times as likely in children with ASD. The prevalence of NTDs in children from our study was higher than the national average of NTDs of 0.1%. The increased odds of NTD in children with ASD suggests additional investigation is needed into the association of vitamin B deficiencies and Autism. This is an important potential association for practitioners to be aware of since military families travel to countries without mandatory folate fortification programs. Further analysis will explore if this relationship persists after controlling for factors that may be associated with both Autism Spectrum Disorders and neural tube defects.