Characteristics and conventional semen parameters of the study population (n = 63)
| Parameters | Exposure (mean±SD) (n = 21) | Internal controls (mean±SD) (n = 23) | P1 | External controls (mean±SD) (n = 19) | P2 |
|---|---|---|---|---|---|
| P1 compared with internal controls; P2 compared with external controls. | |||||
| Age (y) | 30.13±9.61 | 29.07±6.91 | 0.655 | 30.61±6.56 | 0.846 |
| Working history (y) | 9.22±7.68 | 6.56±5.03 | 0.057 | 8.49±6.11 | 0.890 |
| Smoking status | |||||
| Non-smoker (%) | 9 (42.9) | 11 (47.8) | 0.741 | 9 (47.4) | 0.775 |
| Smoker (%) | 12 (57.1) | 12 (52.2) | 10 (52.6) | ||
| Smoking years | 8.43±5.68 | 7.12±4.98 | 0.804 | 7.78±6.01 | 0.852 |
| Semen parameters | |||||
| Sperm concentration (million/ml) | 52.89±35.04 | 52.92±36.94 | 1.00 | 59.78±17.02 | 0.830 |
| Subjects <20 million sperm/ml (%) | 2 (9.50) | 2 (8.75) | 0.924 | 2 (10.52) | 0.916 |
| Sperm motility (% motile) | 55.73±11.88 | 57.20±10.53 | 0.713 | 56.42±16.17 | 0.868 |
| Subjects <50% motile sperm (%) | 4 (19.03) | 7 (30.37) | 0.384 | 7 (36.82) | 0.208 |