Table 1.
Comparison of type 2 diabetic men with and without subnormal free testosterone concentrations
| Group 1 testosterone concentrations |
Group 2 testosterone concentrations |
|||||
|---|---|---|---|---|---|---|
| Subnormal free | Normal free | P value | Subnormal free | Normal free | P value | |
| n | 50 | 148 | 30 | 72 | ||
| Age (years) | 59 ± 11 | 55 ± 12 | 0.08 | 61 ± 10 | 53 ± 11 | 0.003 |
| BMI (kg/m2) | 37.2 ± 8.8 | 34.2 ± 6.6 | 0.02 | 36.3 ± 7.5 | 35.6 ± 7.6 | 0.68 |
| Total testosterone (ng/dL) | 198 [136–259], 217 ± 171 | 347 [276–449], 385 ± 166 | <0.001 | 175 [128–234], 175 ± 78 | 292 [235–367], 319 ± 129 | <0.001 |
| Free testosterone (ng/dL) | 2.8 [2.0–3.04], 2.8 ± 0.76 | 5.18 [4.19–6.58], 5.5 ± 1.81 | <0.001 | 2.77 [2.34–3.33], 2.95 ± 0.60 | 5.76 [4.75–6.77], 5.87 ± 1.57 | <0.001 |
| Bioavailable testosterone (ng/dL) | 62 [47–69], 64 ± 17 | 118 [94–154], 125 ± 42 | <0.001 | |||
| Total estradiol (ng/dL) | 3.4 [2.2–4.8], 3.4 ± 1.5 | 3.9 [3.1–4.6], 4.0 ± 1.5 | 0.006 | 1.25 [0.04–2.60], 1.86 ± 2.03 | 1.95 [1.23–3.08], 2.10 ± 1.21 | 0.03 |
| Free estradiol (ng/dL) | 0.047 [0.035–0.068], 0.053 ± 0.026 | 0.063 [0.046–0.077], 0.066 ± 0.027 | 0.003 | 0.025 [0.012–0.047], 0.038 ± 0.039 | 0.045 [0.028–0.071], 0.048 ± 0.027 | 0.008 |
| Bioavailable estradiol (ng/dL) | 1.86 [1.32–2.55], 2.0 ± 0.94 | 2.39 [1.84–2.95], 2.5 ± 1.02 | 0.001 | |||
| SHBG (nmol/L) | 27 [20–38], 33 ± 27 | 26 [17–36], 28 ± 14 | 0.42 | 23 [15–36], 26 ± 14 | 23 [15–29], 25 ± 11 | 0.45 |
| Free estradiol/free testosterone (%) | 1.9 [1.3–3.0], 2.2 ± 1.4 | 1.2 [0.9–1.6], 1.3 ± 0.6 | 0.002 | 1.2 [0.6–1.9], 1.4 ± 1.5 | 0.8 [0.4–1.3], 0.9 ± 0.5 | 0.006 |
| LH (IU/L) | 4.0 [1.7–5.9], 4.1 ± 2.8 | 4.2 [2.9–6.5], 5.2 ± 3.8 | 0.10 | 4.8 [3.0–7.0], 4.6 ± 2.4 | 4.5 [3.2–6.5], 5.6 ± 3.9 | 0.13 |
| FSH (IU/L) | 5.6 [3.2–8.4], 5.9 ± 3.6 | 5.9 [3.2–9.1], 7.1 ± 6.2 | 0.69 | 6.8 [4.9–11.9], 7.3 ± 5.0 | 4.5 [3.5–9.0], 7.3 ± 7.5 | 0.36 |
| Prolactin (mg/L) | 7.0 [5.0–8.4], 8.2 ± 7.2 | 6.6 [5.1–8.6], 7.9 ± 5.6 | 0.88 | 7.0 [4.7–8.3], 6.6 ± 2.4 | 6.3 [4.7–9.0], 7.3 ± 3.8 | 0.41 |
| HbA1c (%) | 6.8 [6.1–8.0], 7.5 ± 1.9 | 7.3 [6.4–9.0], 7.9 ± 2.0 | 0.34 | 7.6 [6.8–9.5], 8.2 ± 2.1 | 7.9 [6.9–9.8], 8.2 ± 1.9 | 0.98 |
| Duration of diabetes (years) | 7 [2–20], 11 ± 9 | 8 [4–13], 9 ± 7 | 0.52 | 11 [2–20], 11 ± 11 | 8 [4–13], 9 ± 8 | 0.56 |
| Use of insulin (%) | 56 | 66 | 0.40 | 70 | 56 | 0.73 |
| Mean insulin dose (IU) | 92 ± 114 | 69 ± 58 | 0.35 | 58 ± 50 | 66 ± 59 | 0.58 |
| Use of oral hypoglycemics (%) | 85 | 88 | 0.99 | 80 | 86 | 0.66 |
| Use of exenatide (%) | 17 | 19 | 0.79 | 20 | 18 | 0.88 |
Group 1: Total estradiol concentrations were measured by immunoassay. Free testosterone and free estradiol concentrations were calculated. Group 2: Total estradiol concentrations were measured by LC-MS/MS. Free testosterone and free estradiol concentrations were measured by equilibrium dialysis. Data are expressed as means ± SD. SHBG, testosterone, and estradiol concentrations were not normally distributed; therefore, medians [25th–75th percentile] are also mentioned. Statistical comparisons of hormonal concentrations were performed after log transformation and adjustment for age and BMI differences in the two groups. Total estradiol and total testosterone concentrations were also adjusted for SHBG. P values are given for comparison between men with and without subnormal free testosterone concentrations.