Table 1.
Semen characteristics and reproductive hormone levels at baseline according to body mass index (BMI)
| Parameter | Body mass index (BMI), kg/m2 | Test for trend* | ||
|---|---|---|---|---|
| 33.3 - 41.6 (n = 14)# |
41.7 - 46.08 (n = 14)# |
46.1 - 60.9 (n = 15)# |
P-value | |
| Sperm concentration (millions/ml) | ||||
| Median (p25, 75) | 54 (25, 102) | 24 (4, 55) | 19 (8, 33) | 0.03 |
| Adjusted back-transformed median (95% CI)a, b, d | 18 (3, 111) | 4 (1, 28) | 5 (1, 39) | 0.02 |
| Semen volume (ml) | ||||
| Median (p25, 75) | 2.9 (2.2, 4.0) | 3.5 (2.2, 5.8) | 3.3 (2.4, 4.0) | 0.92 |
| Adjusted back-transformed median (95% CI)a, b, c, d, e | 1.7 (0.8, 3.5) | 2.6 (1.3, 5.4) | 1.7 (0.7, 4.1) | 0.74 |
| Total sperm count (millions) | ||||
| Median (p25, 75) | 209 (62, 230) | 93 (11, 204) | 46 (22, 76) | 0.03 |
| Adjusted back-transformed median (95% CI)a, e | 70 (32, 156) | 31 (11, 90) | 23 (9, 56) | 0.02 |
| Normal sperm morphology (%) | ||||
| Median (p25, 75) | 9 (6, 11) | 5 (2, 13) | 5 (1, 9) | 0.28 |
| Adjusted back-transformed median (95% CI)a, c, d, e | 10 (0, 244) | 7 (0, 103) | 2 (0, 61) | 0.04 |
| Motile sperm (%) | ||||
| Median (p25, 75) | 73 (64, 77) | 57 (43, 71) | 55 (40, 67) | 0.06 |
| Adjusted back-transformed median (95% CI)h | 59 (21, 163) | 46 (16, 132) | 19 (7, 51) | 0.005 |
| DNA fragmentation index, DFI (%) | ||||
| Median (p25, 75) | 10 (7, 18) | 16 (12, 32) | 18 (12, 23) | 0.23 |
| Adjusted back-transformed median (95% CI)a, b, d, e, f | 9 (4, 19) | 12 (6, 25) | 10 (4, 24) | 0.70 |
| Testosterone (nmol/L) | ||||
| Median (p25, 75) | 9.2 (7.8, 11.4) | 8.0 (6.4, 11.0) | 7.0 (6.0, 8.0) | 0.005 |
| Adjusted mean (95% CI)b, d, e, g | 8.7 (5.3, 12.2) | 9.1 (6.0, 12.2) | 6.3 (2.6, 10.1) | 0.04 |
| Estradiol (nmol/L) | ||||
| Median (p25, 75) | 0.10 (0.09, 0.15) | 0.15 (0.14, 0.17) | 0.19 (0.16, 0.23) | < 0.005 |
| Adjusted mean (95% CI)b, d, e, g | 0.11 (0.07, 0.16) | 0.13 (0.09, 0.17) | 0.18 (0.13, 0.23) | < 0.005 |
| SHBG (nmol/L) | ||||
| Median (p25, 75) | 18.0 (12.4, 22.7) | 17.4 (14.7, 25.0) | 22.8 (15.2, 27.5) | 0.62 |
| Adjusted mean (95% CI)b, d, e, g | 20.5 (13.0, 27.9) | 21.5 (14.9, 28.1) | 24.2 (16.1, 32.3) | 0.07 |
| FSH (IU/L) | ||||
| Median (p25, 75) | 2.8 (2.6, 3.7) | 4.5 (2.2, 5.9) | 3.2 (2.2, 3.4) | 0.36 |
| Adjusted back-transformed median (95% CI)b, d, e, g | 2.8 (1.7, 4.6) | 3.9 (2.5, 6.2) | 2.2 (1.3, 3.9) | 0.30 |
| LH (IU/L) | ||||
| Median (p25, 75) | 3.6 (2.9, 4.6) | 4.9 (3.7, 6.8) | 3.9 (2.8, 5.2) | 0.86 |
| Adjusted back-transformed median (95% CI)b, d, e, g | 3.1 (2.0, 4.8) | 4.7 (3.1, 7.0) | 2.9 (1.8, 4.8) | 0.60 |
| Inhibin B (pg/ml) | ||||
| Median (p25, 75) | 160 (141, 220) | 123 (117, 170) | 120 (86, 171) | 0.004 |
| Adjusted back-transformed median (95% CI)d, e | 156 (94, 257) | 128 (84, 195) | 110 (64, 188) | 0.04 |
| AMH (ng/ml) | ||||
| Median (p25, 75) | 3.6 (3.1, 4.3) | 2.9 (1.8, 4.0) | 3.3 (2.2, 4.9) | 0.60 |
| Adjusted back-transformed median (95% CI)b, d, e, g | 2.8 (1.7, 4.7) | 2.3 (1.5, 3.7) | 2.5 (1.4, 4.3) | 0.68 |
| Free androgen index (FAI) | ||||
| Median (p25, 75) | 59.1 (43.2, 75.8) | 45.3 (38.9, 62.8) | 33.4 (28.7, 44.0) | 0.008 |
| Adjusted back-transformed median (95% CI)b, d, e, g | 55.0 (36.3, 73.6) | 46.3 (29.7, 62.8) | 28.5 (8.3, 48.7) | < 0.005 |
| Free testosterone/free estradiol ratio | ||||
| Median (p25, 75) | 95.2 (76.8, 108.4) | 56.2 (45.8, 82.8) | 35.6 (32.0, 56.1) | < 0.005 |
| Adjusted median (95% CI)b, d, g | 69.4 (45.7, 105.2) | 59.5 (40.0, 88.3) | 32.5 (20.8, 51.0) | < 0.005 |
| LH/free testosterone ratio | ||||
| Median (p25, 75) | 0.07 (0.06, 0.09) | 0.10 (0.08, 0.11) | 0.10 (0.08, 0.17) | 0.005 |
| Adjusted back-transformed median (95% CI)b, d, e, g | 0.07 (0.04, 0.10) | 0.11 (0.07, 0.17) | 0.11 (0.06, 0.18) | 0.009 |
| Testis volume (ml) | ||||
| Median (p25, 75) | 13.5 (11.0, 14.0) | 10.0 (8.0, 17.5) | 12.0 (10.0, 15.0) | 0.80 |
| Adjusted back-transformed median (95% CI)a, d, e | 8.5 (4.0, 18.5) | 8.0 (4.0, 16.0) | 10.0 (4.0, 24.0) | 0.98 |
p, percentile; CI, confidence interval. *Trends were tested by Spearman's rank correlation test and multiple linear regression analyses with BMI entered as a continuous explanatory variable. #This number of participants (n) relates to the hormone parameters except for AMH. The numbers in the groups for the following variables are: sperm concentration n = 13, n = 14, n = 14; semen volume n = 13, n = 8, n = 9; total sperm count n = 13, n = 7, n = 10; morphology n = 12, n = 14, n = 14; motility n = 13, n = 14, n = 14; DFI n = 11, n = 14, n = 14; testis volume: n = 5, n = 9, n = 7, AMH n = 13, n = 13, n = 15.
The medians are adjusted for the following: abstinence time (a), current smoking (b), season (c), diseases in the reproductive organs (d), age (e), spillage at semen sampling (f) fever (g) and minutes from ejaculation to start of semen analysis (h).