TY - JOUR
T1 - Association Between Environmental Air Pollution and Thyroid Cancer and Nodules
T2 - A Systematic Review
AU - Vohra, Varun
AU - Yesantharao, Lekha V.
AU - Stemme, Rachel
AU - Seal, Stella M.
AU - Morris-Wiseman, Lilah F.
AU - McAdams-DeMarco, Mara
AU - Mady, Leila J.
AU - Deziel, Nicole C.
AU - Biswal, Shyam
AU - Ramanathan, Murugappan
AU - Mathur, Aarti
N1 - Publisher Copyright:
Copyright 2024, Mary Ann Liebert, Inc., publishers.
PY - 2024/12/1
Y1 - 2024/12/1
N2 - Background: The global incidence of thyroid cancer has increased over the past several decades. While this increase is partially due to increased detection, environmental pollutants have also emerged as a possible contributing factor. Our goal was to perform a systematic review to assess the relationship between environmental air pollution and thyroid cancer. Methods: Systematic literature search was performed using PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases for original articles published prior to March 2024, investigating outdoor air pollution and thyroid cancer/nodules (PROSPERO CRD42024517624). Inclusion criteria included quantitative reporting of pollutant levels and effect size. Specific pollutants included ozone (O3), particulate matter less than 2.5 (PM2.5) or 10 microns in diameter (PM10), sulfur dioxide (SO2), nitric oxides (NOx), carbon monoxide (CO), and polyaromatic hydrocarbons (PAHs). Study design, sample size, pollution assessment method, covariates, and strength/direction of associations between pollutants and thyroid cancer/nodule detection were extracted, and descriptive synthesis was utilized to summarize pertinent findings. Risk of bias was assessed using the National Heart, Lung, and Blood Institute quality assessment tool. Results: Of 1294 identified studies, 11 met inclusion criteria. Over 6 million patients from diverse regions were represented across studies. Pollutants studied included O3 in 5 studies; PM2.5, PM10, SO2, and NOx in 3 studies; unspecified PM and CO in 2 studies; and PAHs in 1 study. Primary outcome was thyroid cancer diagnosis among 9 studies and thyroid nodule detection in 2. All studies examining NOx and O3 reported increased risks ranging from 1.03 to 1.5-fold and 1.1 to 1.3-fold, respectively. Both studies assessing PM2.5 reported 1.18 to 1.23-fold increased odds of thyroid cancer diagnosis, and the magnitude of association increased with increasing duration or concentration of PM2.5 Inconsistent results were observed for levels of CO, PM10, and SO2. Conclusion: While an emerging body of literature suggests a potential association between air pollution and thyroid cancer, the quality of evidence is limited by study design constraints, variability in exposure assessment, and inconsistent adjustment for potential confounding factors. The heterogeneity in study designs and methodologies present challenges in interpreting results, underscoring the need for standardized approaches in future research.
AB - Background: The global incidence of thyroid cancer has increased over the past several decades. While this increase is partially due to increased detection, environmental pollutants have also emerged as a possible contributing factor. Our goal was to perform a systematic review to assess the relationship between environmental air pollution and thyroid cancer. Methods: Systematic literature search was performed using PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases for original articles published prior to March 2024, investigating outdoor air pollution and thyroid cancer/nodules (PROSPERO CRD42024517624). Inclusion criteria included quantitative reporting of pollutant levels and effect size. Specific pollutants included ozone (O3), particulate matter less than 2.5 (PM2.5) or 10 microns in diameter (PM10), sulfur dioxide (SO2), nitric oxides (NOx), carbon monoxide (CO), and polyaromatic hydrocarbons (PAHs). Study design, sample size, pollution assessment method, covariates, and strength/direction of associations between pollutants and thyroid cancer/nodule detection were extracted, and descriptive synthesis was utilized to summarize pertinent findings. Risk of bias was assessed using the National Heart, Lung, and Blood Institute quality assessment tool. Results: Of 1294 identified studies, 11 met inclusion criteria. Over 6 million patients from diverse regions were represented across studies. Pollutants studied included O3 in 5 studies; PM2.5, PM10, SO2, and NOx in 3 studies; unspecified PM and CO in 2 studies; and PAHs in 1 study. Primary outcome was thyroid cancer diagnosis among 9 studies and thyroid nodule detection in 2. All studies examining NOx and O3 reported increased risks ranging from 1.03 to 1.5-fold and 1.1 to 1.3-fold, respectively. Both studies assessing PM2.5 reported 1.18 to 1.23-fold increased odds of thyroid cancer diagnosis, and the magnitude of association increased with increasing duration or concentration of PM2.5 Inconsistent results were observed for levels of CO, PM10, and SO2. Conclusion: While an emerging body of literature suggests a potential association between air pollution and thyroid cancer, the quality of evidence is limited by study design constraints, variability in exposure assessment, and inconsistent adjustment for potential confounding factors. The heterogeneity in study designs and methodologies present challenges in interpreting results, underscoring the need for standardized approaches in future research.
KW - environmental air pollution
KW - particulate matter
KW - thyroid cancer
KW - thyroid nodules
UR - http://www.scopus.com/inward/record.url?scp=85210312267&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85210312267&partnerID=8YFLogxK
U2 - 10.1089/thy.2024.0317
DO - 10.1089/thy.2024.0317
M3 - Review article
C2 - 39552469
AN - SCOPUS:85210312267
SN - 1050-7256
VL - 34
SP - 1451
EP - 1464
JO - Thyroid
JF - Thyroid
IS - 12
ER -