Clinical and Translational Research
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Methodol. May 20, 2022; 12(3): 99-106
Published online May 20, 2022. doi: 10.5662/wjm.v12.i3.99
COVID-19 and thyroid disease: An infodemiological pilot study
Ioannis Ilias, Charalampos Milionis, Eftychia Koukkou
Ioannis Ilias, Charalampos Milionis, Eftychia Koukkou, Department of Endocrinology, Diabetes & Metabolism, Elena Venizelou Hospital, Athens GR-11521, Greece
Author contributions: All authors conceived this work, searched the literature, analyzed the data, performed the analyses, and wrote this manuscript.
Institutional review board statement: The statement is not applicable since this is a web-based data study.
Clinical trial registration statement: The statement is not applicable since this is a web-based data study.
Informed consent statement: The statement is not applicable since this is a web-based data study.
Conflict-of-interest statement: The authors declare that they have no conflict of interest to disclose.
Data sharing statement: All the data for this study can be obtained from the publicly available sources
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Ioannis Ilias, MD, PhD, Consultant Physician-Scientist, Department of Endocrinology, Diabetes & Metabolism, Elena Venizelou Hospital, 2, Elena Venizelou Sq., Athens GR-11521, Greece.
Received: November 23, 2021
Peer-review started: November 23, 2021
First decision: February 8, 2022
Revised: February 11, 2022
Accepted: March 26, 2022
Article in press: March 26, 2022
Published online: May 20, 2022
Research background

Google Trends searches for symptoms and/or diseases may reflect actual disease epidemiology. Recently, Google Trends searches for coronavirus disease 2019 (COVID-19)-associated terms have been linked to the epidemiology of COVID-19. Some studies have linked COVID-19 with thyroid disease.

Research motivation

Since the use of Google Trends to study a wide range of medical topics is becoming more widespread and the available research on COVID-19-related thyroid disease is conflicting, with this work we aimed to look at the issue of COVID-19-related thyroid disease from a different angle, namely, that of digital epidemiology, since the latter may be a useful adjunct to classical epidemiology.

Research objectives

We assessed worldwide COVID-19 cases per se vs COVID-19-associated Google Trends searches and thyroid-associated Google Trends searches for 92 wk.

Research methods

We collected data on worldwide weekly GT searches regarding “COVID-19”, “severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)”, “coronavirus”, “smell”, “taste”, “cough”, “thyroid”, “thyroiditis”, and “subacute thyroiditis” for 92 wk and worldwide weekly COVID-19 cases' statistics in the same time period. The study period was split in half (approximately corresponding to the preponderance of different SARS-COV-2 virus variants) and in each time period we performed cross-correlation analysis and mediation analysis.

Research results

Significant positive cross-correlation function values were noted in both time periods. More in detail, COVID-19 cases per se were found to be associated with no lag with Google Trends searches for COVID-19 symptoms in the first time period and in the second time period to lead searches for symptoms, COVID-19 terms, and thyroid terms.

Research conclusions

Searches for a non-specific symptom or COVID-19 search terms mostly led Google Trends thyroid-related searches, in the second time period. This time frame/sequence particularly in the second time period (noted by the preponderance of the SARS-COV-2 delta variant), lends some credence to associations of COVID-19 cases per se with (apparent) thyroid disease (via searches for them).

Research perspectives

Given the relatively recent onset of SARS-CoV-2 virus infection, the available monitoring data are limited in time and therefore long-term studies are needed to evaluate even longer-term effects on the endocrine glands. Research into the virus continues to grow, shedding more light on the real health risks posed by COVID-19. Ideally, it would be interesting to assess time and localization-delimited Google Trends searches with the corresponding thyroid disease incidence, as reported by “sentinel” physicians or as recorded in healthcare databases, to verify the associations observed. Understanding the nature of a pandemic of this magnitude means saving human lives and proper knowledge of ways to prevent further infection.