Semen quality of fertile men from four cities in Japan
| Observed | Adjusted | ||
|---|---|---|---|
| Mean (SD) | Median (5–95) | Median (95% CI) | |
| Semen volume (ml) | |||
| Entire study population | 3.1 (1.5) | 3.0 (1.0–6.0) | 3.0 (2.9 to 3.2) |
| Sapporo | 3.2 (1.6) | 3.0 (1.0–6.1) | 2.9 (2.7 to 3.1) |
| Osaka | 2.9 (1.5) | 2.6 (1.0–5.2) | 2.7 (2.5 to 3.0) |
| Kanazawa | 3.5 (1.6) | 3.2 (1.4–6.0) | 3.2 (3.0 to 3.4) |
| Fukuoka | 2.8 (1.4) | 2.6 (1.0–5.2) | 2.7 (2.5 to 3.0) |
| p Value | 0.006 | ||
| Sperm concentration (mill/ml) | |||
| Entire study population | 105 (83) | 84 (18–257) | 84 (76 to 92) |
| Sapporo | 110 (84) | 95 (22–244) | 89 (76 to 104) |
| Osaka | 97 (79) | 76 (15–253) | 80 (70 to 93) |
| Kanazawa | 105 (76) | 84 (17–259) | 80 (70 to 92) |
| Fukuoka | 115 (102) | 89 (21–263) | 98 (80 to 120) |
| p Value | 0.04 | ||
| Total sperm count (mill) | |||
| Entire study population | 317 (294) | 239 (38–818) | 255 (230 to 282) |
| Sapporo | 331 (300) | 255 (44–800) | 264 (223 to 312) |
| Osaka | 266 (239) | 198 (26–712) | 222 (195 to 267) |
| Kanazawa | 357 (307) | 284 (50–848) | 266 (228 to 309) |
| Fukuoka | 324 (350) | 229 (48–1007) | 276 (221 to 346) |
| p Value | 0.07 | ||
| Motile spermatozoa (%) | |||
| Entire study population | 67 (21) | 66 (31–100) | 77 (74 to 79) |
| Sapporo | 62 (18) | 65 (28–87) | 66 (61 to 70) |
| Osaka | 85 (19) | 92 (46–100) | 94 (93 to 95) |
| Kanazawa | 55 (15) | 56 (30–77) | 60 (48 to 56) |
| Fukuoka | 60 (14) | 60 (34–82) | 69 (62 to 74) |
| p Value | <0.0001 | ||
| Morphologically normal spermatozoa (%)* | |||
| Entire study population | 9.8 (6.1) | 8.5 (1.5–21.5) | 9.3 (8.4 to 10.3) |
| Sapporo | |||
| Osaka | 8.6 (5.2) | 8 (1.0–1.08.5) | 8.4 (7.3 to 9.6) |
| Kanazawa | 11.8 (6.9) | 10.5 (2.0–24.5) | 11.3 (10.2 to 12.4) |
| Fukuoka | 8.1 (5.1) | 7.0 (1.5–18.0) | 7.7 (6.4 to 9.0) |
| p Value | <0.0001 | ||
Observed: results based on raw data.
Adjusted median and 95% CI calculated by linear regression analysis.
Semen volume, sperm concentration and total sperm counts adjusted to a period of ejaculation abstinence of 96 h for a 32-year-old man.
Motility controlled for duration from ejaculation to assessment (30 min for a 32-year-old man).
Morphology adjusted to winter season for a 32-year-old man. See text for further explanation.
p Value based on regression analyses, comparing all four groups.
(5–95), 5–95th percentile.