High Maternal Vitamin B12 Linked to Increased Risk for Offspring Childhood Autism

by | Jun 8, 2023 | 2023, Autism, Brain Health, Infant and Children's Health, Pregnancy and Lactation, Vitamin B12

Written by Taylor Woosley, Staff Writer. Findings of the population-based study show a significant association between maternal vitamin B12 levels in the highest quintile and offspring childhood autism (p = 0.026), with a close to significance association noted in the lowest quintile (p = 0.064).

autism - brain healthAutism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and restricted/repetitive patterns of behavior1. In addition to these main symptoms, people with ASD tend to suffer from comorbidities such as intellectual disability, gastrointestinal problems, and eating and sleeping disorders2. ASD is believed to be a lifelong disability, but the clinical presentation and level of functioning may change over time3.

Prenatal maternal diet is a critical factor in offspring neurodevelopment and emerging evidence suggests that prenatal diet may also play a role in the etiology of ASD4. Research has shown that too little and too much folic acid or B12 supplementation can both lead to an increased risk of ASD5. Furthermore, the deficiency of B12 may contribute to neurological impairments such as motor disturbances, cognitive impairment, and brain cell loss, all commonly known as symptoms of ASD6.

Sourander et al. conducted a population-based study to examine the association between maternal serum vitamin B12 levels in early pregnancy and the risk of ASD diagnosis in offspring. Furthermore, they investigated the association between maternal serum vitamin B12 levels in early pregnancy and specific ASD subtypes in offspring. Data included in the study was from the Finnish Prenatal Study of Autism Spectrum Disorders (FIPS-A), a case-control study including all singleton live births between 1987-2005 in Finland. Additionally, data from the Finnish Maternity Cohort of the Northern Finland Biobank Borealis (FMC), a nationwide serum bank consisting of 2 million serum samples collected during the first and early second trimesters of pregnancy from over 950,000 women, was also included in the study.

All ASD cases were registered in the Care Register for Health Care (CRHC) with ICD-10 and ICD-9 diagnoses. Control cases were singleton offspring without a diagnosis of ASD or Intellectual disability. Each case was matched with one control on date of birth, sex, and place of birth. A total of 1558 cases and 1558 matched controls were included in the final analysis. Potential confounders, such as maternal smoking, previous births, history of maternal psychopathology, and substance abuse history, suggested to be associated with both maternal vitamin B12 and ASD, were selected.

Maternal vitamin B12 levels were examined as a continuous variable and categorized into quintiles. Continuous potential confounders were tested with X2, Student’s t and Fisher’s exact tests and/or Pearson chi-square tests for categorical variables for the association with log-transformed maternal vitamin B12 level among controls. Conditional logistic regression models for the matched sets were utilized to test potential confounders for an association with ASD.

The mean age of ASD diagnosis for cases was 6.57 years. The mean vitamin B12 level among cases was 114.40 pmol/L, and it was 116.80 pmol/L among controls. Gender distribution was 19.5% female and 80.5% male in cases and controls. Significant findings of the study are as follows:

  • A significant association was observed between maternal vitamin B12 levels in the highest quintile (≥81st percentile) and offspring childhood autism (aOR 1.59, 95% CI 1.06-2.41, p = 0.026) and the association was close to significance in the lowest quintile (aOR 1.49, 95% CI 0.92-2.26, p = 0.064).
  • After adjusting for maternal psychopathology and gestational age, the findings were similar with a significant association between childhood autism and maternal vitamin B12 in the highest quintile in model I (aOR 1.59, 95% CI 1.06-2.42, p = 0.027).

Results of the study suggest that low and high levels of maternal vitamin B12 during early pregnancy was associated with offspring childhood autism. Further studies are necessary to better comprehend a specific mechanism that would produce the association between maternal vitamin B12 levels and childhood autism. Study limitations include the lack of measuring neonatal vitamin B12 levels, the lack of collecting maternal vitamin B12 levels in later pregnancy, and the potential for residual confounding by unmeasured factors such as prenatal vitamin supplementation or maternal medications during pregnancy.

Source: Sourander, Andre, Sanju Silwal, Heljä-Marja Surcel, Susanna Hinkka-Yli-Salomäki, Subina Upadhyaya, Ian W. McKeague, Keely Cheslack-Postava, and Alan S. Brown. “Maternal Serum Vitamin B12 during Pregnancy and Offspring Autism Spectrum Disorder.” Nutrients 15, no. 8 (2023): 2009.

© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

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Posted June 7, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

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