Accessible Requires Authentication Published by De Gruyter September 18, 2018

Seasonality of month of birth in children and adolescents with autoimmune thyroiditis: a continuing conundrum

Ioannis Kyrgios, Styliani Giza, Vasiliki Rengina Tsinopoulou, Ioanna Maggana, Anna-Bettina Haidich and Assimina Galli-Tsinopoulou



The aim of this study was to analyze the seasonal birth month pattern in young patients with autoimmune thyroiditis and compare it with youth controls.


Medical records of a total of 298 children and adolescents of Greek origin, with a diagnosis of Hashimoto thyroiditis (HT) before the age of 21 years that were born from 1987 to 2010 were retrospectively reviewed. In addition, 298 consecutive subjects that were born from 1988 to 2012 and evaluated in a tertiary unit for any reason, served as controls, provided that they had no personal or family history of thyroid or any other autoimmune disease.


Significant differences were found between children and adolescents with HT and healthy controls in the yearly pattern of month of birth distribution (p=0.029). During month-by-month analysis, it was shown that the highest and lowest predispositions to HT were among those born in spring (March) (odds ratio [OR] 2.34, p=0.005), and autumn (November) (OR 0.49, p=0.035), respectively. A binary logistic regression model also revealed that season of birth and sex were the only factors that remained related to HT disease, even after adjustment for confounding factors such as year of birth and age (p<0.001, Nagelkerke r-square 0.151).


This study suggests that the effect of certain seasonal factors during fetal development, reflected by the seasonal differences in birth pattern, in children and adolescents with autoimmune thyroiditis could contribute to long-term programming of an autoimmune response against the thyroid gland. Further studies are needed to demonstrate a clear cause and effect relationship between month of birth and HT.

Corresponding author: Assimina Galli-Tsinopoulou, MD, PhD, Professor in Pediatrics-Pediatric Endocrinology, 4th Department of Pediatrics, Faculty of Health Sciences, Medical School, Aristotle University of Thessaloniki, Papageorgiou General Hospital, Ring Road Nea Efkarpia, 56403 Thessaloniki, Greece, Phone/Fax: +302310991537

  1. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: None declared.

  3. Employment or leadership: None declared.

  4. Honorarium: None declared.

  5. Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.


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Received: 2018-01-27
Accepted: 2018-08-13
Published Online: 2018-09-18
Published in Print: 2018-10-25

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