Table 1. Descriptive statistics and comparisons of standard semen parameters and DFI between men aged <40 y and ≥40 y.
| Parameters n median (range) mean±SD | < 40 y (n = 902) | ≥ 40 y (n = 222) | p |
| Age (y) | 902 32.00 (18.00–39.00) 31.05 (5.07) |
222 43 (40.00–70.00) 45.41 (6.11) |
0.00001 |
| Semen volume (mL) | 902 3.35 (0.50–12.00) 3.54 (1.66) |
222 3.00 (0.15–10.00) 3.10 (1.63) |
0.00012 |
| Sperm concentration (×106/mL) | 902 33.56 (0.001–347.700) 47.03 (44.46) |
222 39.50 (0.10–216.00) 50.97 (46.57) |
0.40039 |
| Total number of spermatozooa (x106) | 902 107.70 (0.002–2109.75) 166.22 (191.67) |
222 105.50 (0.15–931.50) 148.72 (154.44) |
0.2374 |
| Morphologically normal spermatozoa (%) | 902 4.00 (0.00–34.00) 5.63 (5.80) |
222 4.00 (0.00–28.00) 4.36 (4.14) |
0.03200 |
| TZI | 845 1.63 (1.02–2.62) 1.65 (0.25) |
218 1.61 (1.21–2.33) 1.62 (0.21) |
0.11902 |
| Progressive motility (%) | 902 40.00 (0.00–90.00) 39.32 (19.73) |
222 41.00 (0.00–88.00) 40.62 (21.76) |
0.40505 |
| Non-progressive motility (%) | 902 14.00 (0.00–59.00) 16.38 (9.80) |
222 11.00 (0.00–54.00) 13.71 (8.86) |
0.00013 |
| Immotile sperms (%) | 902 41.00 (2.00–100.00) 44.27 (19.15) |
222 44.00 (1.00–99.00) 45.66 (23.12) |
0.61195 |
| Eosin-negative spermatozoa – live cells (%) | 897 68.00 (0.00–98.00) 65.18 (17.73) |
220 66.00 (2.00–99.00) 64.41 (20.76) |
0.95651 |
| Hos-test-positive spermatozoa – live cells (%) | 631 62.00 (0.00–93.00) 59.25 (17.95) |
190 65.00 (10.00–94.00) 60.24 (18.19) |
0.47225 |
| Round cells concentration (x 106/mL) | 862 0.16 (0.00–37.34) 0.74 (2.16) |
216 0.10 (0.00–11.00) 0.51 (1.22) |
0.21214 |
| Peroxidase-positive cells (x106/mL) | 869 0.00 (0.00–11.70) 0.37 (1.06) |
216 0.00 (0.00–6.00) 0.28 (0.74) |
0.27913 |
| DFI (%) | 248 10.82 (0.77–65.14) 13.37 (10.31) |
88 18.47 (0.76–75.94) 19.77 (13.12) |
0.00001 |
DFI – sperm DNA fragmentation index, n – number of subjects, SD – standard deviation, TZI – teratozoospermia index, p – significance of differences between compared groups, Mann–Whitney U test