Table 1.
Basic characteristics of the enrolled studies.
| Study | Exposure | Period | Study design | Location | Major ethnicity | Age | Groups | Positive findings | NOS |
|---|---|---|---|---|---|---|---|---|---|
| Selevan, 2000 | PM10, TSPs, SO2, CO, Nox | 1993-1994 | Cross-sectional | Czech | Caucasian | 18 | Residents in urban or rural areas | Lower progressive motility, total motility, normal morphology rate, and chromatin structure | 8 |
| De Rosa, 2003 | Traffic pollutants | 2000-2002 | Cross-sectional | Italy | Caucasian | 23-62 | Workers at motorways or offices | Lower total motility, progressive motility, concentration, VSL, VCL, LIN, and ALH | 6 |
| Rubes, 2005 | PM10, PAH, SO2, NOx | 1995-1997 | Longitudinal | Czech | Caucasian | 19-25 | Residents in winter and summer | None | 9 |
| Guven, 2008 | Traffic pollutants | NM | Cross-sectional | Turkey | Caucasian | 35.2 ± 6.4; 33.7 ± 6.7 | Workers at motorways or offices | Lower normal morphology rate, concentration, progressive motility | 6 |
| Boggia, 2009 | Traffic pollutants | 2000-2004 | Cross-sectional | Italy | Caucasian | 23-57 | Workers at motorways or offices | Lower total motility and progressive motility | 6 |
| Rubes, 2010 | PM2.5, SO2, NO, CO, O3, PAH, Benzo | 2007 | Longitudinal | Czech | Caucasian | 33.6 ± 5.3 | Residents in winter and spring | Lower total motility and DFI | 9 |
| Calogero, 2011 | Traffic pollutants | NM | Cross-sectional | Italy | Caucasian | 20-47 | Workers at motorways or offices | Lower normal morphology rate, concentration, total sperm count, progressive motility, and DFI | 6 |
| Zhou, 2014 | PM10, SO2, NO2 | 2007 | Cross-sectional | China | Asian | 20-40 | Residents in urban or rural areas | Lower normal morphology rate, VSL, VCL, and VAP | 8 |
| Wu, 2016 | PM10 | 2013-2015 | Cross-sectional | China | Asian | 34.4 ± 5.4 | Residents with different PM exposure | Lower concentration and total count | 9 |
| Liu, 2017 | SO2 | 2013-2015 | Cross-sectional | China | Asian | 34.4 ± 5.4 | Residents with different PM exposure | Lower total count, concentration, progressive motility, and total motility | 9 |
| Lao, 2018 | PM2.5 | 2001, 2004 | Cross-sectional | China | Asian | 31.9 ± 4.3 | Residents with different PM exposure | Lower normal morphology and higher sperm concentration | 8 |
ALH: amplitude of lateral movement of sperm head; DFI: DNA fragmentation index; LIN: linearity of sperm motion; NM: not mentioned; NOS: Newcastle-Ottawa Scale; TSPs: PM-total suspended particulates; VCL: sperm curvilinear velocity; VSL: sperm linear velocity.