The Association Between Long-Term Air Pollution Exposure and Risk of Thyroid Eye Disease: A Nationwide Cohort Study in Taiwan.

Purpose: Thyroid eye disease (TED) is a significant orbital disorder commonly associated with Graves' disease, characterized by retrobulbar tissue enlargement and various ocular symptoms. While the pathophysiology involves autoimmune processes, the potential influence of air pollution on TED remains unexplored. This study aims to investigate the association between long-term air pollution exposure and the risk of TED in Taiwanese adults with thyroid disease.

Methods: A nationwide cohort study was conducted utilizing data from Taiwan's National Health Insurance Research Database. Adult patients newly diagnosed with thyroid disease between 2003 and 2013 were included. Exposure to 10 air pollutants over a decade was assessed and linked to patients' residential locations. Cox regression models were used to analyze the dose-response relationship between air pollutants and TED risk, adjusting for confounders.

Results: The final cohort comprised 7340 patients, among whom 218 developed TED. Significant associations were observed between long-term exposure to 10 air pollutants and increased TED risk. A 1 standard deviation increase in the 10-year average exposure to sulfur dioxide, CO, particles less than 10 µm in diameter, particles less than 2.5 µm in diameter, nitrogen oxides, nitrogen monoxide, nitrogen dioxide, total hydrocarbons, nonmethane hydrocarbons, and methane corresponded to elevated TED risk of 26%, 62%, 74%, 49%, 47%, 32%, 56%, 27%, 20%, and 24%.

Conclusions: This study provides the first evidence linking long-term air pollution exposure to increased TED risk in individuals with thyroid disease. The findings underscore the importance of addressing air pollution as a modifiable risk factor for TED and advocate for the implementation of strategies to mitigate air pollution's adverse health effects. Further research is warranted to elucidate the underlying mechanisms and inform targeted interventions for TED prevention and management.