# Prevalence of Subclinical Hypothyroidism in Information Technology Professionals With High Screen Exposure

## TL;DR

This study finds that 11.7% of IT professionals with high screen exposure have subclinical hypothyroidism, linked to prolonged screen time and thyroid autoimmunity.

## Contribution

The study is the first to examine subclinical hypothyroidism prevalence and its occupational risk factors in IT professionals with high screen exposure.

## Key findings

- 11.7% of IT professionals had subclinical hypothyroidism.
- High screen exposure (≥9 hours/day) was significantly associated with subclinical hypothyroidism.
- Anti-TPO antibody positivity was a strong independent predictor of subclinical hypothyroidism.

## Abstract

Background: Subclinical hypothyroidism (SCH) represents a frequently overlooked thyroid dysfunction, particularly in asymptomatic individuals. In occupational contexts where prolonged screen exposure and sedentary behavior are prevalent, such as in the information technology (IT) sector, there is a growing need to evaluate endocrine health through a focused lens. This study addresses a critical gap in the literature by examining the prevalence of SCH and its associations with screen time, shift work, and thyroid autoimmunity in a digitally active workforce.

Objective: To estimate the prevalence of subclinical hypothyroidism among IT professionals and to examine its association with screen exposure duration, anti-thyroid peroxidase (anti-TPO) antibody status, and occupational factors, including shift work.

Methods: An analytical cross-sectional study was conducted between February and June 2024 among 350 IT professionals aged 22-55 years in Chennai, India. Participants with daily screen exposure ≥8 hours were recruited. Data was collected using a structured questionnaire and clinical evaluation. Thyroid function tests (thyroid-stimulating hormone (TSH), free triiodothyronine (free T3) and free thyroxine (free T4)) and anti-TPO antibody levels were measured using standard chemiluminescence and enzyme-linked immunosorbent assay (ELISA) assays. Subclinical hypothyroidism was defined as TSH>4.0 mIU/L with normal levels of free T3 and T4. Anti-TPO positivity was defined as antibody levels >35 IU/mL. Multivariable logistic regression was performed to identify independent predictors of SCH.

Results: Out of 350 participants (mean age: 32.8±6.9 years; 183 males (52.3%)), 41 individuals (11.7%) were found to have subclinical hypothyroidism. Anti-TPO antibody positivity was observed in 62 participants (17.7%), and among those with SCH, 19 (46.3%) were antibody positive. High screen exposure (≥9 hours/day) was reported by 278 participants (79.4%) and was present in 36 of the 41 SCH cases (87.8%). Screen exposure ≥9 hours/day was significantly associated with SCH (adjusted odds ratio (OR): 2.14; 95% CI: 1.01-4.52; p=0.045). Anti-TPO positivity emerged as a strong independent predictor of SCH (adjusted OR: 5.33; 95% CI: 2.41-11.76; p<0.001). Although shift work was more common among SCH participants (51.2%) compared to euthyroid individuals (36.6%), the association was not statistically significant after adjustment (adjusted OR: 1.76; p=0.064). No significant associations were found with sex, BMI, smoking, alcohol use, or physical inactivity.

Conclusion: This study highlights a substantial prevalence of subclinical hypothyroidism (11.7%) in IT professionals with prolonged screen exposure. Prolonged digital engagement and anti-TPO antibody positivity were identified as key risk factors, suggesting a role for occupational exposures and autoimmunity in early thyroid dysfunction. These findings support the need for targeted endocrine screening protocols in screen-intensive workforces to enable early detection and preventive care.