Outdoor Air Pollutants May Be Linked to Development of Thyroid Nodules

Researchers examined whether concentrations of particulate matter 2.5 µm and 10 µm, nitrogen dioxide, sulfur dioxide, carbon monoxide, or ozone were linked with prevalence of thyroid nodule.

There is a linear association between exposure to various outdoor air pollutants — including particulate matter 2.5 µm  or 10 µm, nitrogen dioxide, sulfur dioxide, carbon monoxide, and ozone — and development of thyroid nodules, according to study results presented at the 89th Annual Meeting of the American Thyroid Association, held October 30 to November 3, 2019, in Chicago, Illinois.

While previous studies have shown that these air pollutants are associated with increased risk for cardiovascular disease and cancer, limited data are available regarding the association between these pollutants and thyroid nodules. The goal of the current study was to explore the association between air pollutants and thyroid nodules in China.

The study included approximately 4.9 million adults who participated in a routine health checkup at Meinian HealthCare Screening Centers in 157 cities in China during 2017. The researchers used data from the National Urban Air Quality Real Time Publishing Platform to calculate the average annual concentrations of air pollutants from 2015 to 2017.

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After adjusting for age, smoking status, thyroid-stimulating hormone level, and other factors, the results showed a significant linear association between each of the 6 air pollutants and thyroid nodule, with odds ratios for a 10 µg/m3 increase ranging from 1.01 (95% CI, 1.01-1.02) for nitrogen dioxide to 1.40 (95% CI, 1.37-1.42) for carbon monoxide.

The risk was relatively lower in women, elderly patients, and individuals with higher urine iodine level.

“This large cross-sectional study found [linear] associations between particulate matter 2.5 µm or 10 µm, nitrogen dioxide, sulfur dioxide, carbon monoxide, and ozone, and thyroid nodule without minimum effective concentration in China,” concluded the researchers.

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Wang S, Song Y, Wei Q, et al. Outdoor air pollutants is a potential risk factor for the increasing prevalence of thyroid nodule: result from 4.9 million Chinese population. Presented at: American Thyroid Association 2019 Annual Meeting; October 30-November 3, 2019; Chicago, IL. Short Call Poster 30.