Climate and air pollution exposure are associated with thyroid function parameters: a retrospective cross-sectional...

Area of Science:

• Endocrinology
• Environmental Health
• Public Health

Background:

• Controversies exist regarding the influence of environmental factors on thyroid function in healthy individuals.
• Understanding these influences is crucial for public health and clinical practice.

Purpose of the Study:

• To investigate the associations between climatic factors, air pollution exposure, and thyroid function parameters.
• To analyze thyroid function fluctuations in a large cohort of healthy individuals.

Main Methods:

• Retrospective analysis of 327,913 individuals' health check data (December 2013 - December 2018).
• Spearman's correlation for climate factors and multiple linear regression for air pollution (PM2.5), adjusting for confounders.
• Subgroup and sensitivity analyses performed based on age, sex, and antibody status.

Main Results:

• Thyroid-stimulating hormone (TSH) and free triiodothyronine (FT3) showed negative correlations with outdoor temperature.
• Free thyroxine (FT4) and the FT4/FT3 ratio positively correlated with temperature.
• Increased fine particulate matter (PM2.5) was linked to decreased FT4 and increased FT3 levels, impacting the FT4/FT3 ratio.

Conclusions:

• Thyroid function parameters are demonstrably associated with climate and air pollution.
• These environmental factors play a role in thyroid function variability.
• The findings underscore the need for public health initiatives to mitigate air pollution exposure.