Table 2. Descriptive statistics and comparisons of standard semen parameters and DFI between men aged <40 y and ≥40 y with normozoospermia.
| Parameters n median (range) mean±SD | < 40 y (n = 367) | ≥ 40 y (n = 81) | p |
| Age (y) | 367 31.00 (18.00–39.00) 30.06 (5.25) |
81 43.00 (40.00–53.00) 43.97 (4.10) |
0.00001 |
| Semen volume (mL) | 367 3.50 (0.80–12.00) 3.86 (1.77) |
81 2.80 (0.80–8.70) 3.30 (1.68) |
0.00219 |
| Sperm concentration (×106/mL) | 367 56.00 (8.90–347.70) 68.05 (50.58) |
81 59.00 (9.20–216.00) 72.49 (46.33) |
0.24677 |
| Total number of spermatozooa (x106) | 367 187.00 (39.00–2109.75) 251.49 (235.54) |
81 171.00 (39.00–931.50) 225.14 (170.72) |
0.56813 |
| Morphologically normal spermatozoa (%) | 367 7.00 (4.00–34.00) 9.40 (6.33) |
81 7.00 (4.00–28.00) 7.62 (4.31) |
0.10451 |
| TZI | 350 1.54 (1.08–2.49) 1.54 (0.20) |
79 1.49 (1.21–1.89) 1.49 (0.15) |
0.03818 |
| Progressive motility (%) | 367 51.00 (32.00–90.00) 52.41 (12.94) |
81 55.00 (32.00–88.00) 56.22 (13.67) |
0.02615 |
| Non-progressive motility (%) | 367 14.00 (1.00–44.00) 15.27 (8.03) |
81 11.00 (3.00–33.00) 13.58 (7.22) |
0.11685 |
| Immotile sperms (%) | 367 32.00 (2.00–66.00) 32.44 (11.63) |
81 30.00 (1.00–58.00) 30.19 (13.05) |
0.23924 |
| Eosin-negative spermatozoa – live cells (%) | 366 74.00 (35.00–98.00) 73.19 (11.34) |
81 80.00 (46.00–99.00) 76.37 (13.23) |
0.01771 |
| Hos-test-positive spermatozoa – live cells (%) | 252 69.50 (28.00–92.00) 67.40 (11.91) |
73 69.00 (40.00–94.00) 69.49 (11.87) |
0.22170 |
|
Round cells concentration (x 106/mL) |
351 0.15 (0.00–37.34) 0.83 (2.88) |
79 0.10 (0.00–11.70) 0.59 (1.52) |
0.97768 |
| Peroxidase-positive cells (x106/mL) | 354 0.00 (0.00–11.56) 0.28 (0.86) |
79 0.00 (0.00–6.00) 0.25 (0.75) |
0.81045 |
| DFI (%) | 116 11.45 (0.77–65.14) 12.74 (9.48) |
44 14.77 (1.00–40.52) 17.68 (10.45) |
0.00518 |
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