Table 2.
Regression coefficients (95% CIs) of semen quality associated with quintiles of SO2 exposure during 0–90 days before the date of semen examination estimated by multi-pollutant models.
| Per IQR increase | VIF | Quintile of SO2 exposure, μg/m3
|
||||||
|---|---|---|---|---|---|---|---|---|
| 4.0–14.4 | 14.5–20.1 | 20.2–26.8 | 26.9–35.2 | 35.3–67.2 | P trend | |||
| SO2 + NO2 | ||||||||
| Sperm concentration | −0.16 (−0.26, −0.06) | 4.12 | 0 (ref) | 0.01 (−0.11, 0.13) | −0.09 (−0.24, 0.05) | −0.20 (−0.36, −0.04) | −0.33 (−0.54, −0.13) | < 0.001 |
| Sperm count | −0.24 (−0.34, −0.14) | 4.08 | 0 (ref) | −0.02 (−0.14, 0.11) | −0.17 (−0.32, −0.02) | −0.33 (−0.50, −0.16) | −0.44 (−0.65, −0.23) | < 0.001 |
| Total motility | −0.09 (−0.18, 0.01) | 4.08 | 0 (ref) | −0.02 (−0.14, 0.10) | −0.03 (−0.17, 0.11) | −0.10 (−0.26, 0.06) | −0.30 (−0.49, −0.10) | 0.002 |
| Progressive motility | −0.06 (−0.16, 0.03) | 4.07 | 0 (ref) | 0.00 (−0.12, 0.12) | −0.01 (−0.15, 0.13) | −0.06 (−0.22, 0.10) | −0.24 (−0.44, −0.05) | 0.011 |
| Total motile sperm count | −0.19 (−0.29, −0.09) | 4.10 | 0 (ref) | −0.02 (−0.14, 0.10) | −0.13 (−0.27, 0.01) | −0.24 (−0.40, −0.08) | −0.40 (−0.60, −0.20) | < 0.001 |
| SO2 + CO | ||||||||
| Sperm concentration | −0.17 (−0.26, −0.08) | 3.39 | 0 (ref) | 0.03 (−0.10, 0.15) | −0.07 (−0.21, 0.08) | −0.17 (−0.33, −0.01) | −0.35 (−0.54, −0.16) | < 0.001 |
| Sperm count | −0.23 (−0.33, −0.14) | 3.36 | 0 (ref) | −0.01 (−0.13, 0.12) | −0.15 (−0.30, −0.00) | −0.30 (−0.46, −0.14) | −0.43 (−0.63, −0.24) | < 0.001 |
| Total motility | −0.10 (−0.19, −0.01) | 3.35 | 0 (ref) | −0.00 (−0.12, 0.12) | 0.01 (−0.13, 0.15) | −0.06 (−0.21, 0.09) | −0.31 (−0.49, −0.13) | < 0.001 |
| Progressive motility | −0.07 (−0.16, 0.01) | 3.35 | 0 (ref) | 0.02 (−0.10, 0.14) | 0.02 (−0.11, 0.16) | −0.02 (−0.17, 0.13) | −0.25 (−0.43, −0.07) | 0.005 |
| Total motile sperm count | −0.19 (−0.28, −0.10) | 3.37 | 0 (ref) | −0.00 (−0.12, 0.12) | −0.09 (−0.24, 0.05) | −0.20 (−0.36, −0.04) | −0.40 (−0.59, −0.21) | < 0.001 |
| SO2 + O3 | ||||||||
| Sperm concentration | −0.15 (−0.24, −0.06) | 3.25 | 0 (ref) | 0.00 (−0.12, 0.13) | −0.11 (−0.25, 0.04) | −0.21 (−0.37, −0.05) | −0.32 (−0.51, −0.13) | < 0.001 |
| Sperm count | −0.22 (−0.31, −0.12) | 3.21 | 0 (ref) | −0.02 (−0.15, 0.11) | −0.18 (−0.33, −0.03) | −0.32 (−0.49, −0.16) | −0.41 (−0.61, −0.22) | < 0.001 |
| Total motility | −0.08 (−0.17, 0.00) | 3.21 | 0 (ref) | −0.03 (−0.15, 0.09) | −0.03 (−0.17, 0.10) | −0.10 (−0.25, 0.06) | −0.26 (−0.44, −0.08) | 0.002 |
| Progressive motility | −0.06 (−0.14, 0.03) | 3.21 | 0 (ref) | −0.00 (−0.12, 0.12) | −0.01 (−0.15, 0.13) | −0.05 (−0.21, 0.10) | −0.20 (−0.39, −0.02) | 0.014 |
| Total motile sperm count | −0.17 (−0.26, −0.08) | 3.23 | 0 (ref) | −0.02 (−0.14, 0.10) | −0.13 (−0.28, 0.01) | −0.23 (−0.39, −0.07) | −0.36 (−0.55, −0.18) | < 0.001 |
| SO2 + NO2 + CO + O3 | ||||||||
| Sperm concentration | −0.18 (−0.29, −0.08) | 4.34 | 0 (ref) | 0.02 (−0.11, 0.14) | −0.09 (−0.24, 0.06) | −0.20 (−0.37, −0.03) | −0.37 (−0.58, −0.17) | < 0.001 |
| Sperm count | −0.26 (−0.36, −0.15) | 4.29 | 0 (ref) | −0.01 (−0.14, 0.12) | −0.17 (−0.32, −0.01) | −0.33 (−0.50, −0.15) | −0.47 (−0.68, −0.25) | < 0.001 |
| Total motility | −0.11 (−0.21, −0.01) | 4.29 | 0 (ref) | −0.01 (−0.13, 0.11) | −0.01 (−0.15, 0.13) | −0.08 (−0.25, 0.08) | −0.34 (−0.53, −0.14) | < 0.001 |
| Progressive motility | −0.08 (−0.18, 0.02) | 4.28 | 0 (ref) | 0.02 (−0.10, 0.14) | 0.01 (−0.13, 0.15) | −0.04 (−0.21, 0.12) | −0.28 (−0.48, −0.08) | 0.004 |
| Total motile sperm count | −0.22 (−0.32, −0.12) | 4.31 | 0 (ref) | −0.01 (−0.13, 0.12) | −0.11 (−0.26, 0.03) | −0.23 (−0.40, −0.06) | −0.44 (−0.64, −0.23) | < 0.001 |
Abbreviations: CI, confidence interval; IQR, interquartile range; SO2, sulfur dioxide; NO2, nitrogen dioxide; CO, carbon monoxide; O3, ozone; VIF, variance inflation factor.