Table 1 Characteristics of included studies
Study ID | Location | Participants | Study period | Number of cases | Male (%) | Elderly (%) | Data source of outcome | Studied pollutants | Outcome level | Study design | Study quality |
|---|---|---|---|---|---|---|---|---|---|---|---|
Chang 2017 [21] | Taipei, Taiwan | All ages | 2012–2015 | 3729 | NA | NA | Medical records (1 hospital) | PM2.5, SO2, NO2 | Emergency room visit, ICD-9 | Time-series | Intermediate |
Cheng 2019 [22] | Kaohsiung, Taiwan | > 17 years | 2007–2013 | 4015 | 63.5% | NA | Medical records (1 hospital) | PM2.5, PM10, SO2, NO2, O3 | Emergency room visit, ICD-9 | Case-crossover | Intermediate |
Duan 2016 [9] | Shijiazhuang, China | ≥18 years | 2013 | 2253 | 53.4% | 55%a | Medical records (7 hospitals) | PM2.5, PM10, SO2, NO2, CO, O3 | Hospital admission, diagnosis | Case-crossover | Intermediate |
Franck 2015 [23] | Santiago, Chile | All ages | 2004–2007 | 44,430 | NA | NA | FONASA and ISAPREs data | PM2.5, PM10, NO2, CO, O3 | Hospital admission, ICD-10 | Case-crossover | Intermediate |
Halonen 2009 [24] | Helsinki, Finland | ≥65 years | 1998–2004 | 10,733 | NA | 100% | Statistics Finland | PM2.5 | Hospital admission, ICD-10 | Time-series | Good |
Hinwood 2006 [25] | Perth, Australia | All ages | 1992–1998 | 10,000 (estimated) | NA | NA | Medical records (all hospitals) | PM2.5, CO, O3 | Unscheduled hospital admission, ICD-9 | Case-crossover | Good |
Kim 2012 [26] | Five counties in Denver metropolitan area, CO, USA | All ages | 2003–2007 | 23,000 (estimated) | NA | 44%b | Colorado Hospital Association data | PM2.5, SO2, NO2 | Nonelective hospital admission, ICD-9 | Time-series | Intermediate |
Liu 2016 [27] | Greater Huston, TX, USA | All ages | 2008–2013 | 1097 | 49.4% | 12.6% | Blue Cross Blue Shield Texas claims data | PM2.5 | Emergency hospital admission, ICD-9 | Time-series | Intermediate |
Malig 2013 [28] | CA, USA | All ages | 2005–2008 | 70,967 | NA | NA | 2 databases maintained by the California OSHPD | PM2.5, PM10 | Emergency room visit, ICD-9 | Case-crossover | Intermediate |
Medina-Ramon 2006 [10] | 36 cities in USA | > 65 years | 1986–1999 | 1,384,813 | NA | 100% | Medicare claims data | PM10, O3 | Emergency hospital admission, ICD-9 | Case-crossover | Intermediate |
Pennington 2019 [29] | Atlanta, GA, USA | All ages | 1998–2010 | 162,000 (estimated) | NA | NA | Medical records (41 hospitals) | PM2.5 | Emergency room visit, ICD-9 | Time-series | Good |
Phosri 2019 [30] | Bangkok, Thailand | All ages | 2006–2014 | 59,000 (estimated) | 43.4%c | 15.7%c | NHSO claims data | PM10, SO2, NO2, CO, O3 | Hospital admission, ICD-10 | Time-series | Good |
Pothirat 2019 [31] | Chiang Mai, Thailand | All ages | 2016–2017 | 325 | NA | NA | Medical records (1 hospital) | PM2.5, PM10, SO2, NO2, CO, O3 | Hospital admission, ICD-10 | Time-series | Intermediate |
Qiu 2014 [32] | Hong Kong | All ages | 2011–2012 | 75,863 | 53.5% | 74.5% | Hospital Authority Corporate Data Warehouse data | PM2.5 | Emergency hospital admission, ICD-9 | Time-series | Good |
Rodopoulou 2015 [33] | Central AR, USA | ≥15 years | 2002–2012 | 2412 | 40.2%c | 7.4%c | UAMS Enterprise Data Warehouse data | PM2.5, O3 | Emergency room visit, ICD-9 | Time-series | Good |
Santus 2012 [34] | Milan, Italy | All ages | 2007–2008 | 5689 | 54.9% | 48.5% | Medical records (5 hospitals) | PM2.5, PM10, SO2, NO2, CO, O3 | Emergency room visit, ICD-9 | Case-crossover | Intermediate |
Tao 2014 [35] | Lanzhou, China | All ages | 2001–2005 | 4559 | 63.1% | 18.5% | Medical records (4 hospitals) | PM10, SO2, NO2 | Hospital admission, ICD-10 | Time-series | Intermediate |
Tasci 2018 [36] | Ankara, Turkey | > 65 years | 2011–2015 | 2606 | 53.2% | 100% | Medical records (1 hospital) | PM2.5, PM10, SO2, NO2, CO | Emergency room visit, diagnosis | Time-series | Intermediate |
Tian 2019 [37] | 184 cities in China | ≥18 years | 2014–2017 | 4.2 million | NA | NA | UEBMI claims data | PM2.5, PM10 | Hospital admission, ICD-10 | Time-series | Good |
Tian 2020 [38] | 184 cities in China | ≥18 years | 2014–2017 | 4.2 million | NA | NA | UEBMI claims data | O3 | Hospital admission, ICD-10 | Time-series | Good |
Winquist 2012 [39] | St. Louis MSA, USA | All ages | 2001–2007 | 98,000 (estimated) | NA | 35.0% | Missouri Hospital Association data (28 hospitals) | PM2.5, O3 | Emergency room visit, ICD-9 | Time-series | Good |