Long-term exposure to PM1 and thyroid diseases in China

Area of Science:

• Environmental Health
• Endocrinology
• Epidemiology

Background:

• Thyroid diseases are globally prevalent and influenced by environmental factors like air pollution.
• This study investigates the association between particulate matter (PM)1 exposure and thyroid disease prevalence in China.

Purpose of the Study:

• To examine the link between PM1 exposure and various thyroid diseases in a large Chinese adult population.
• To explore the dose-response relationship and the role of iodine status in PM1-associated thyroid dysfunction.

Main Methods:

• Analysis of data from 73,900 adults across 31 Chinese provinces.
• Utilized a high-resolution spatial-temporal model to estimate PM1 and PM2.5 levels.
• Assessed thyroid disease prevalence using thyroid function tests and evaluated associations with PM1 using multivariate-adjusted ORs.

Main Results:

• Higher PM1 exposure was significantly associated with increased prevalence of overt hypothyroidism, autoimmune thyroiditis (AIT), and TgAb positivity.
• A linear dose-response relationship was observed between PM1 concentration and AIT and TgAb positivity.
• PM1 exposure was linked to autoimmune overt hypothyroidism, with iodine status modifying susceptibility; a 1% increase in the PM1/PM2.5 ratio correlated with increased overt and subclinical hypothyroidism.

Conclusions:

• PM1 exposure is associated with thyroid diseases, especially AIT and TgAb positivity, with iodine status playing a key modifying role.
• PM1 may be a critical component of the risk associated with PM2.5 exposure for thyroid disease.
• Further prospective studies are recommended to confirm these associations and understand causality.