Table 1.
Descriptive information for all 19 included studies
| Study | Study design | Location | Sample size | Air pollutants measured | Study duration | Thyroid outcome measured | Exposure window |
|---|---|---|---|---|---|---|---|
| Chamot et al. [41] | Regional Registry Analysis | Picardy Region, France | 6,249 | PM2.5, PM10 | 2021 | TSH (neonatal) | Third trimester |
| Ghassabian et al. [42] | Multi-Cohort Analysis | Amsterdam, Netherlands (ABCD) | 9,931 total | PM2.5, PM10, NO2, NOx, PM2.5−10, PM2.5absorbance | 2003–2004 | TSH, hypothyroxinemia (maternal) | First trimester |
| Rotterdam, Netherlands (Generation R) | PM2.5, PM10, NO2, NOx, PM2.5−10, PM2.5absorbance | 2002–2006 | |||||
| Spain (INMA) | PM2.5, PM10, NO2, NOx, PM2.5−10, PM2.5absorbance | 2003–2008 | |||||
| Crete, Greece (Rhea) | PM2.5, PM10, PM2.5−10, PM2.5absorbance | 2007–2008 | |||||
| Massachusetts, United States (Project Viva) | PM2.5, NO2 | 1999–2002 | |||||
| Gong et al. [43] | Prospective Cohort | Henan Province, China | 1,049 | PM2.5, PM10 | 2017–2019 | FT4, TSH (maternal) | First trimester |
| Harari-Kremer et al. [44] | Historical Cohort Study | Israel | 696, 461 |
PM2.5, PM10 − 2.5, NO2, NOx |
2009–2015 | CHT (neonatal) | Full pregnancy |
| Howe et al. [45] | Retrospective Cohort | California, United States | 2,050 | PM2.5, PM10, NO2, O3, NOx | 1994–1997 | TT4 (neonatal) | Full pregnancy |
| Ilias et al. [46] | Retrospective Cohort | Athens, Greece | 293 | PM2.5, PM10, NO2 | 2012–2018 | TSH (maternal) | Nine months preceding second and third trimesters |
| Irizar et al. [47] | Prospective Cohort | Gipuzkoa, Spain | 463 pairs | PM2.5, NO2 | 2006–2008 | TT4 (neonatal) | Full pregnancy |
| Janssen et al. [33] | Birth Cohort | Limburg, Belgium | 499 pairs | PM2.5 | 2010–2014 | FT3, FT4, FT4/FT3 ratio, TSH (maternal and fetal) | Third trimester |
| Li et al. [48] | Birth Cohort | Wuhan, China | 551 | PM2.5 | 2013–2015 | FT3, FT4, FT4/FT3 ratio, TSH (maternal) | Preconception; First Trimester |
| Nourouzi & Chamani [49] | Birth Cohort | Isfahan City, Iran | 200 | PM2.5, CO | 2019–2020 | TSH (fetal) | Full pregnancy |
| Qi et al. [50] | National Database Analysis | China | 367 cities (30 provinces) | SO2, CO, NO2, O3 | 2014–2015 | CHT (neonatal) | Full pregnancy |
| Qiu et al. [51] | Retrospective Cohort | Jinhua, China | 2,528 | PM2.5, PM10, SO2, CO, NO2, PM2.5-bound metals [Al, As, Be, Cr, Pb, Mn, Ni, Se, Tl, Ba] | 2018 | FT3, FT4, FT4/FT3 ratio, TSH (maternal) | First trimester |
| Shang et al. [52] | National Database Analysis | China | 30 provinces | PM2.5, PM10 | 2014–2015 | CHT (neonatal) | Full pregnancy |
| Sun et al. [53] | Retrospective Case-Control | Beijing, China | 3,180 (795 cases, 2,385 controls) | PM2.5, PM10 | 2012–2020 | Hypothyroidism (maternal) | Preconception and early pregnancy |
| Wang et al. [54] | Prospective Birth Cohort | Nanjing, China | 433 pairs | PM2.5, OM, BC, SO42−, NO3−, NH4+, soil dust | 2014–2015 | FT4 (maternal), TSH (maternal and neonatal) | First trimester |
| Zeng et al. [55] | Birth Cohort | Guiyu and Haojiang, China | 204 pairs | PM2.5 | 2011–2012 | FT4, FT3, TSH (fetal) | Full pregnancy |
| Zhang et al. [56] | Prospective Birth Cohort | Wuhan, China | 921 | PM2.5, PM10 | 2013–2014 | FT4, FT3, FT4/FT3 ratio, TSH (maternal) | First trimester |
| Zhao et al. [57] | Cohort Study | Shanghai, China | 8,077 | PM2.5, NO2 | 2014–2015 | FT4, TSH, hypothyroxinemia (maternal) | First and second trimester |
| Zhou et al. [58] | Prospective Birth Cohort | Shanghai, China | 1,060 pairs | PM2.5, 17 inorganic constituents above 50% detection rate (Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Pb) | 2016–2018 | FT4, FT3, FT4/FT3 ratio, TSH (maternal) | Early pregnancy |
Abbreviations: TSH, thyroid stimulating hormone; FT3, triiodothyronine; FT4, thyroxine; CHT, congenital hypothyroidism; TT4, total thyroxine; PM2.5, particulate matter of 2.5 microns; PM10, particulate matter of 10 microns; PM2.5−10, particulate matter of 2.5–10 microns; NO2, nitrogen dioxide; O3, ozone; NOx, nitrogen oxides; CO, carbon monoxide; SO2, sulfur dioxide; As, arsenic; Be, beryllium; Cr, chromium; Mn, manganese; Se, selenium; Tl, thallium; Ba, barium; Na, sodium; Al, aluminum; Si, silicon; P, phosphorous; S, sulfur; Cl, chlorine; K, potassium; Ca, calcium; Ti, titanium; V, vanadium; Fe, iron; Ni, nickel; Cu, copper; Zn, zinc; Pb, lead; OM, organic matter; BC, black carbon; SO42−, sulfate; NO3−, nitrate; NH4+, ammonium