Serum 25-hydroxyvitamin D, vitamin B12, and folate concentrations in children with autism spectrum disorder: a case-control study from a tertiary care center in Turkiye

Halenur Teke; Hilal Tüter Mavi; Ahmet Bolat; Melikşah Safa Üçok; Şahin Bodur; Mehmet Ayhan Cöngöloğlu

doi:10.32322/jhsm.1961635

Serum 25-hydroxyvitamin D, vitamin B12, and folate concentrations in children with autism spectrum disorder: a case-control study from a tertiary care center in Turkiye

Abstract

Aims: This study aimed to compare serum 25-hydroxyvitamin D [25(OH)D], vitamin B12, and folate concentrations between children with autism spectrum disorder (ASD) and typically developing controls, and to examine their relationship with autism symptom severity. Methods: This case-control study combined prospective clinical evaluation with retrospective retrieval of routine serum 25(OH)D, vitamin B12, and folate measurements from electronic medical records. The study included 140 children aged 2-8 years, comprising 70 children with ASD and 70 age- and gender-comparable typically developing controls, at a tertiary university hospital in Turkiye. ASD diagnosis was established according to DSM-5 criteria, and symptom severity was assessed using the Childhood Autism Rating Scale (CARS). Group comparisons, correlation analyses, and multivariable linear regression were performed. Results: Children with ASD had lower mean serum 25(OH)D concentrations than controls (mean difference: -3.43 ng/ml, 95% CI: -6.07 to -0.79; Cohen’s d=-0.43; p=0.011). Vitamin B12 and folate concentrations did not differ significantly between groups. The frequencies of vitamin D, vitamin B12, and folate deficiencies were also comparable between the ASD and control groups. Within the ASD group, none of the evaluated micronutrients differed by ASD severity or correlated with CARS scores. In the multivariable linear regression analysis, ASD group status and season of blood sampling remained independently associated with serum 25(OH)D concentrations after adjustment for age, gender, and body-mass index z-score. Conclusion: Children with ASD had lower mean serum 25(OH)D concentrations than typically developing controls, although vitamin D deficiency rates were comparable between the groups. This finding suggests that vitamin D status may warrant attention as a modifiable aspect of nutritional health in this population but should not be interpreted as an ASD-specific biomarker. Longitudinal and intervention-based studies are needed to clarify the directionality and clinical significance of this association and the potential benefit of supplementation in ASD.

Keywords

Ethical Statement

The study was approved by the Scientific Research Ethics Committee of the University of Health Sciences, Gülhane Training and Research Hospital (Decision No: 2025/192, Decision Date: 06.11.2025). Written informed consent was obtained from the parents or legal guardians of all participants after the study aims and procedures had been explained in detail. Age- and developmentally appropriate assent was also obtained from the children whenever feasible. All study procedures adhered to the ethical standards set forth in the Declaration of Helsinki.

Thanks

The authors would like to thank the children and their families who participated in this study. We also thank the clinical staff of the Department of Child and Adolescent Psychiatry and the pediatric outpatient clinic for their support during the clinical evaluation and data collection processes.

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Details

Primary Language

English

Subjects

Child and Adolescent Psychiatry

Journal Section

Research Article

Authors

Halenur Teke ^*
0009-0001-0143-3890
Türkiye

Hilal Tüter Mavi
0009-0005-3341-8774
Türkiye

Ahmet Bolat
0000-0001-6653-0045
Türkiye

Melikşah Safa Üçok
0009-0008-7025-6606
Türkiye

Şahin Bodur
0000-0002-4942-7932
Türkiye

Mehmet Ayhan Cöngöloğlu
0000-0003-2880-2446
Türkiye

Publication Date

September 19, 2026

Submission Date

June 13, 2026

Acceptance Date

August 8, 2026

Published in Issue

Year 2026 Volume: 9 Number: 5

DOI

https://doi.org/10.32322/jhsm.1961635

IZ

https://izlik.org/JA79ZS45LT

Cite

RIS / Bibtex

APA

Teke, H., Tüter Mavi, H., Bolat, A., Üçok, M. S., Bodur, Ş., & Cöngöloğlu, M. A. (2026). Serum 25-hydroxyvitamin D, vitamin B12, and folate concentrations in children with autism spectrum disorder: a case-control study from a tertiary care center in Turkiye. Journal of Health Sciences and Medicine, 9(5), 1370-1378. https://doi.org/10.32322/jhsm.1961635

AMA

1.Teke H, Tüter Mavi H, Bolat A, Üçok MS, Bodur Ş, Cöngöloğlu MA. Serum 25-hydroxyvitamin D, vitamin B12, and folate concentrations in children with autism spectrum disorder: a case-control study from a tertiary care center in Turkiye. J Health Sci Med / JHSM. 2026;9(5):1370-1378. doi:10.32322/jhsm.1961635

Chicago

Teke, Halenur, Hilal Tüter Mavi, Ahmet Bolat, Melikşah Safa Üçok, Şahin Bodur, and Mehmet Ayhan Cöngöloğlu. 2026. “Serum 25-Hydroxyvitamin D, Vitamin B12, and Folate Concentrations in Children With Autism Spectrum Disorder: A Case-Control Study from a Tertiary Care Center in Turkiye”. Journal of Health Sciences and Medicine 9 (5): 1370-78. https://doi.org/10.32322/jhsm.1961635.

EndNote

Teke H, Tüter Mavi H, Bolat A, Üçok MS, Bodur Ş, Cöngöloğlu MA (September 1, 2026) Serum 25-hydroxyvitamin D, vitamin B12, and folate concentrations in children with autism spectrum disorder: a case-control study from a tertiary care center in Turkiye. Journal of Health Sciences and Medicine 9 5 1370–1378.

IEEE

[1]H. Teke, H. Tüter Mavi, A. Bolat, M. S. Üçok, Ş. Bodur, and M. A. Cöngöloğlu, “Serum 25-hydroxyvitamin D, vitamin B12, and folate concentrations in children with autism spectrum disorder: a case-control study from a tertiary care center in Turkiye”, J Health Sci Med / JHSM, vol. 9, no. 5, pp. 1370–1378, Sept. 2026, doi: 10.32322/jhsm.1961635.

ISNAD

Teke, Halenur - Tüter Mavi, Hilal - Bolat, Ahmet - Üçok, Melikşah Safa - Bodur, Şahin - Cöngöloğlu, Mehmet Ayhan. “Serum 25-Hydroxyvitamin D, Vitamin B12, and Folate Concentrations in Children With Autism Spectrum Disorder: A Case-Control Study from a Tertiary Care Center in Turkiye”. Journal of Health Sciences and Medicine 9/5 (September 1, 2026): 1370-1378. https://doi.org/10.32322/jhsm.1961635.

JAMA

1.Teke H, Tüter Mavi H, Bolat A, Üçok MS, Bodur Ş, Cöngöloğlu MA. Serum 25-hydroxyvitamin D, vitamin B12, and folate concentrations in children with autism spectrum disorder: a case-control study from a tertiary care center in Turkiye. J Health Sci Med / JHSM. 2026;9:1370–1378.

MLA

Teke, Halenur, et al. “Serum 25-Hydroxyvitamin D, Vitamin B12, and Folate Concentrations in Children With Autism Spectrum Disorder: A Case-Control Study from a Tertiary Care Center in Turkiye”. Journal of Health Sciences and Medicine, vol. 9, no. 5, Sept. 2026, pp. 1370-8, doi:10.32322/jhsm.1961635.

Vancouver

1.Halenur Teke, Hilal Tüter Mavi, Ahmet Bolat, Melikşah Safa Üçok, Şahin Bodur, Mehmet Ayhan Cöngöloğlu. Serum 25-hydroxyvitamin D, vitamin B12, and folate concentrations in children with autism spectrum disorder: a case-control study from a tertiary care center in Turkiye. J Health Sci Med / JHSM. 2026 Sep. 1;9(5):1370-8. doi:10.32322/jhsm.1961635