Table 1 shows the characteristics of the study participants. The average age was 45.02 years, and the average BMD was 1.16 g/cm2. The remaining ovaries were on both sides in 129 patients, one side in 73 patients, and none (both sides removed) in 5 patients. There were 70 (33.82%) post-menopausal patients, and the average age at menopause was 46.84 years. There were 106 patients with a history of hormone therapy within the previous year, and a total of 171 patients had a history of ovarian surgery.
Table 1
Baseline characteristics of participants
| N | Mean |
Age (years) | 207 | 45.02 ± 2.73 |
Weight (kg) | 207 | 55.31 ± 9.02 |
Height (cm) | 207 | 159.23 ± 5.67 |
Body mass index (kg/m2) | 207 | 21.80 ± 3.27 |
Systolic Blood Pressure (mmHg) | 198 | 121.98 ± 13.04 |
Diastolic Blood Pressure (mmHg) | 198 | 78.98 ± 10.29 |
FSH (mIU/mL) | 202 | 33.42 ± 41.84 |
E2 (pg/mL) | 201 | 92.98 ± 107.48 |
TSH (µIU/mL) | 198 | 1.72 ± 1.11 |
Free T4 (µg/dL) | 199 | 1.09 ± 0.17 |
AMH (ng/mL) | 166 | 0.36 ± 0.57 |
BMD (g/cm2) | 207 | 1.16 ± 0.15 |
Current hormonal therapy (%) | 106 | 51.21 |
Surgical treatment (%) | 171 | 82.61 |
Residual ovary | | |
Bilateral (%) | 129 | 62.32 |
Unilateral (%) | 73 | 35.27 |
None (%) | 5 | 2.42 |
Postmenopausal (%) | 70 | 33.82 |
Age at menopause (years) | | 46.84 ± 3.33 |
Data were presented as means ± standard deviation or number of cases (%) |
Current hormonal therapy is defined as the administration of hormonal agents within 1 year before the initial measurement. |
BMD was measured at the lumbar spine using dual-energy X-ray absorptiometry (DXA). |
BMD: bone mineral density, FSH: follicle-stimulating hormone, AMH: anti-Müllerian hormone, TSH: thyroid-stimulating hormone, E2: oestradiol, T4: thyroxine |
First, we studied factors affecting BMD. Table 2a shows the correlation between BMD and other factors at the initial testing. Pearson correlation analysis identified a significant correlation between BMD and the following factors: age exhibited a negative correlation (r = − 0.1523, p = 0.0285), body weight, and BMI showed a positive correlation (r = 0.4539; p < 0.0001 and r = 0.3996; p < 0.0001, respectively), whereas FSH showed a negative correlation (r = − 0.3126, p < 0.0001) with BMD. Similarly, free T4 showed a negative correlation (r = − 0.1604, p = 0.0236) and AMH showed a positive correlation (r = 0.2183, p = 0.047) with BMD. FSH and AMH showed a significant correlation with BMD according to the multiple regression analysis adjusted for age and body weight (FSH: β = −0.00071, p = 0.0038; AMH: p = 0.018) (Table 2b).
Table 2 a) Correlation between BMD and initial measurement
|
R2
|
P-value
|
Age (years)
|
0.023
|
0.0285
|
Weight (kg)
|
0.206
|
<0.0001
|
Height (cm)
|
0.194
|
0.0052
|
Body mass index (kg/m2)
|
0.160
|
<0.0001
|
Systolic Blood Pressure (mmHg)
|
0.017
|
0.0647
|
Diastolic Blood Pressure (mmHg)
|
0.019
|
0.0559
|
FSH (mIU/mL)
|
0.098
|
<0.0001
|
E2 (pg/mL)
|
0.004
|
0.371
|
TSH (μIU/mL)
|
0.004
|
0.3604
|
Free T4 (μg/dL)
|
0.026
|
0.0236
|
AMH (ng/mL)
|
0.048
|
0.0047
|
b) Correlations between BMD, FSH, and AMH adjusted for age and weight: partial regression coefficients
|
N
|
Β
|
P-value
|
FSH (mIU/mL)
|
202
|
-0.00071
|
0.0038
|
AMH (ng/mL)
|
166
|
0.05006
|
0.018
|
AMH: anti-Müllerian hormone, BMD: bone mineral density, E2: oestradiol, FSH: follicle-stimulating hormone, T4: thyroxine, TSH: thyroid-stimulating hormone
Next, we analysed the rate of change in BMD. Table 3 summarises the data of 142 patients analysed to determine the annual rate of BMD change. The average period between the initial and follow-up testing was 1.41 ± 0.53 (range: 0.25–2.75) years. The changes in BMD and the annual rate of BMD change were 0.02 g/cm2 and − 0.53%/year, respectively.
Table 3
Baseline characteristics of participants who underwent follow-up measurements
| N | Mean |
Age (years) | 142 | 45.01 ± 2.63 |
Weight (kg) | 142 | 55.60 ± 9.57 |
Height (cm) | 141 | 159.05 ± 5.79 |
Body mass index (kg/m2) | 141 | 21.92 ± 3.37 |
Systolic Blood Pressure (mmHg) | 138 | 122.26 ± 11.65 |
Diastolic Blood Pressure (mmHg) | 137 | 78.83 ± 9.40 |
FSH (mIU/mL) | 139 | 32.74 ± 41.58 |
E2 (pg/mL) | 138 | 91.51 ± 108.28 |
TSH (µIU/mL) | 136 | 1.79 ± 1.17 |
Free T4 (µg/dL) | 136 | 1.08 ± 0.16 |
BMD (g/cm2) | 142 | 1.15 ± 0.16 |
BMD change (g/cm2) | 141 | 0.02 ± 0.02 |
BMD rate of change (%/year) | 141 | -0.53 ± 2.55 |
Interval between initial and follow-up visit (years) | 141 | 1.41 ± 0.53 |
Current hormonal therapy (%) | 83 | 58.45 |
Surgical treatment (%) | 122 | 85.92 |
Residual ovary | | |
Bilateral (%) | 90 | 63.38 |
Unilateral (%) | 48 | 33.80 |
None (%) | 4 | 2.82 |
Postmenopausal (%) | 53 | 37.32 |
Age at menopause (years) | | 46.77 ± 3.41 |
Data are presented as means ± SD or number of cases (%) |
BMD: bone mineral density, E2: oestradiol, FSH: follicle-stimulating hormone, T4: thyroxine, TSH: thyroid-stimulating hormone |
We examined factors that affected the rate of BMD change. Table 4 shows the correlation between changes in BMD and physical/endocrinological factors measured at the initial test. TSH levels showed a negative correlation (p = 0.0221) with BMD. Other factors were not significantly correlated with the rate of change in BMD.
Table 4
Correlation between change in annual rates of BMD (%/year) and initial measurement
| R2 | P-value |
Age (years) | 0.01925 | 0.1009 |
Weight (kg) | 0.001046 | 0.7034 |
Height (cm) | 0.01331 | 0.1747 |
Body mass index (kg/m2) | 0.0002558 | 0.8512 |
Systolic Blood Pressure (mmHg) | 0.006861 | 0.3359 |
Diastolic Blood Pressure (mmHg) | 0.0004704 | 0.8021 |
FSH (mIU/mL) | 0.002262 | 0.5796 |
E2 (pg/mL) | 0.003724 | 0.4771 |
TSH (µIU/mL) | 0.03873 | 0.0221 |
Free T4 (µg/dL) | 0.0007232 | 0.7569 |
AMH (ng/mL) | 0.003598 | 0.5224 |
BMD (g/cm2) | 0.02527 | 0.0597 |
AMH: anti-Müllerian hormone, BMD: bone mineral density, E2: oestradiol, FSH: follicle-stimulating hormone, T4: thyroxine, TSH: thyroid-stimulating hormone |
We performed a multinomial logistic regression analysis to elucidate the risk factors for annual BMD decrease. The physical/endocrinological factors of each group of participants divided according to tertiles based on the rate of BMD change as per initial and follow-up testing are presented in Table 5. The average ages of the mild bone loss, moderate bone loss, and severe bone loss groups were 44.68 years, 45.09 years, and 45.34 years, respectively, with no significant difference between them. Similarly, the average body weights were 54.33 kg, 56.60 kg and 55.75 kg, respectively, for the three groups, exhibiting no significant differences. Figure 1a depicts the annual rate of BMD change in each group. The annual rates of BMD change in the mild, moderate, and severe bone loss groups were 2.07 ± 2.24%/year, 0.64 ± 0.50%/year, and 3.03 ± 1.12%/year, respectively. Figure 1b shows the TSH values for each group. The TSH values of the three groups were 1.42 ± 0.65 µIU/mL, 1.79 ± 1.28 µIU/mL, and 2.16 ± 1.34 µIU/mL, respectively. There were significant differences between the groups. A greater rate of decrease in BMD was associated with a higher TSH level. Similarly, Fig. 1c shows the average age at menopause in each group. The average age at menopause was 48.04 years, 46.80 years and 45.13 years, respectively, and exhibited a significant difference. A greater rate of decrease in BMD was associated with a significantly higher average age at menopause. Figure 1d illustrates the results of the multinomial logistic regression analysis of TSH levels corrected for age and BMI. The relative risk of the two remaining groups in comparison with the mild bone loss group was 1.69 ± 0.45 (95% confidence interval [CI] 1.01–2.85) in the moderate bone loss group and 2.15 ± 0.57 (95% CI 1.28–3.61) in the severe bone loss group, indicating a significant difference. Multinomial logistic regression analysis with other factors, including FSH and AMH, did not identify a significant increase in the risk of bone loss.
Table 5
Physical and hormonal characteristics among women categorised based on the annual rates of change in BMD
| Mild bone density loss (n = 47) | Moderate bone density loss (n = 47) | Severe bone density loss (n = 47) |
Age (years) | 44.68 ± 2.45 | 45.09 ± 2.53 | 45.34 ± 2.88 |
Weight (kg) | 54.33 ± 9.47 | 56.60 ± 9.46 | 55.75 ± 9.90 |
Height (cm) | 158.29 ± 5.78 | 159.69 ± 5.65 | 159.38 ± 5.91 |
Body mass index (kg/m2) | 21.66 ± 3.48 | 22.10 ± 3.26 | 21.91 ± 3.38 |
Systolic Blood Pressure (mmHg) | 121.72 ± 10.69 | 119.91 ± 11.63 | 124.50 ± 11.77 |
Diastolic Blood Pressure (mmHg) | 79.30 ± 9.82 | 77.36 ± 9.88 | 79.39 ± 8.26 |
FSH (mIU/mL) | 37.34 ± 50.03 | 21.60 ± 22.63 | 39.73 ± 45.66 |
E2 (pg/mL) | 97.77 ± 116.95 | 109.96 ± 116.26 | 66.24 ± 87.95 |
TSH (µIU/mL) | 1.42 ± 0.65 | 1.79 ± 1.28 | 2.16 ± 1.34 |
Abnormally high TSH levels (n, %) | 0 (0) | 2 (4.3) | 4 (8.5) |
Free T4 (µg/dL) | 1.08 ± 0.17 | 1.07 ± 0.15 | 1.08 ± 0.17 |
BMD (g/cm2) | 1.11 ± 0.19 | 1.17 ± 0.14 | 1.15 ± 0.13 |
BMD change (g/cm2) | 0.02 ± 0.02 | 0.01 ± 0.00 | 0.03 ± 0.02 |
BMD rate of change (%/year) | 2.07 ± 2.24 | -0.64 ± 0.50 | -3.03 ± 1.12 |
Postmenopausal (n, %) | 23 (48.94) | 15 (31.91) | 15 (31.91) |
Age at menopause (years) | 48.04 ± 2.10 | 46.8 ± 4.07 | 45.13 ± 3.76 |
Data are presented as means ± SD or number of cases (%). |
Abnormally high TSH levels: ≥ 4.23 µIU/mL |
BMD: bone mineral density, E2: oestradiol, FSH: follicle-stimulating hormone, T4: thyroxine, TSH: thyroid-stimulating hormone |