Is elevated baseline SHBG associated with increased ovulation?

Figures & data

Table 1. Characteristics of the subjects.

Variable	Non-ovulation (215)	Ovulation (739)	P value
Biometric features at baseline
Sex hormone-binding globulin, nmol/L	33.72 ± 25.39	45.16 ± 31.32	0.000
Age, yr	27.4 ± 3.46	28.05 ± 3.26	0.012
BMI, kg/m2	25.47 ± 4.68	23.84 ± 4.06	0.000
Modified Ferriman-Gallwey score	2.96 ± 2.96	3.03 ± 2.71	0.754
Acne score	0.38 ± 0.72	0.45 ± 0.77	0.262
Fasting serum levels at baseline
LH, mIU/mL	11.37 ± 5.25	10.25 ± 6.11	0.008
FSH, mIU/mL	6.05 ± 1.48	6.1 ± 1.72	0.739
LH to FSH ratio	1.91 ± 0.83	1.75 ± 1.21	0.030
Progesterone, ng/ml	2.87 ± 6.61	2.51 ± 4.59	0.365
Estradiol, pg/mL	217.28 ± 97.17	285.61 ± 357.37	0.000
Total testosterone, ng/dL	1.79 ± 0.65	1.63 ± 0.64	0.001

Table 2. Multivariate analysis of predictors of ovulation according to the multiple logistic regression analysis.

Variable	OR	95%CI	P value	P value adjusted treatment
Age, yr	1.063	1.009–1.119	0.0209	0.0211
BMI, kg/m2	0.922	0.884–0.962	0.0002	0.0011
LH to FSH ratio	0.791	0.654–0.956	0.0153	0.0539
Estradiol, pg/mL	1.002	1.000–1.003	0.0102	0.0211
Total testosterone, ng/dL	0.653	0.494–0.863	0.0027	0.0029
SHBG, μg/mL	1.008	1.000-1.015	0.0364	0.0434

Table 3. HR for Ovulation across quartiles of serum SHBG, testosterone, and estradiol.

	No. of Ovulation / No. at Risk	HR (95% CI)	P value
SHBG, μg/mL
Q1 (≤2.5)	160/238	1.00 (referent)
Q2 (2.5–3.8)	180/239	1.278 (1.023,1.597)	0.0307
Q3 (3.8–6.2)	191/240	1.282 (1.016,1.618)	0.0362
Q4 (≥6.2)	208/237	1.538 (1.211,1.953)	0.0004
Per-quartile increase		1.138 (1.054,1.229)	0.0009
Per-quartile increase, adjusted for testosterone		1.139 (1.055,1.229)	0.0009
Q4 vs. Q1-3		1.267 (1.062,1.511)	0.0085
Q4 vs. Q1-3, adjusted for testosterone*		1.263 (1.059,1.507)	0.0093
Testosterone, ng/dl
Q1 (≤34.6)	197/234	1.00 (referent)
Q2 (34.6–45.8)	192/240	0.919 (0.746,1.132)	0.4266
Q3 (45.8–58.8)	167/239	0.755 (0.607,0.938)	0.0112
Q4 (≥58.8)	178/236	0.856 (0.682,1.073)	0.1780
Per-quartile increase		0.933 (0.868,1.004)	0.0622
Q4 vs. Q1-3		0.983 (0.821,1.176)	0.8486
Q4 vs. Q1-3, adjusted for SHBG*		0.975 (0.814,1.168)	0.7820
Estradiol, pg/ml
Q1 (≤158.9)	198/237	1s.00 (referent)
Q2 (158.9–199.5)	168/237	0.807 (0.654,0.996)	0.0453
Q3 (199.5–265.7)	167/238	0.838 (0.676,1.039)	0.1075
Q4 (≥265.7)	201/237	1.259 (1.011,1.568)	0.0397
Per-quartile increase		1.072 (0.996,1.154)	0.0624

*SHBG and Testosterone entered as quartiles

Table 4. Univariate analysis of relationship of SHBG level with various pathological factors.

Variable	SHBG		P value	P value adjusted treatment
	Mean ± SD	Range
Ovulation			<0.0001	<0.0001
Yes (n = 725)	44.61 ± 30.71	7.75–180.00
No (n = 196)	34.75 ± 26.17	6.57–180.00
Conception			0.0120	0.0140
Yes (n = 294)	46.14 ± 30.70	7.97–180.00
No (n = 627)	40.81 ± 29.62	6.57–180.00
Pregnancy			0.0183	0.0214
Yes (n = 200)	46.94 ± 29.04	9.59–180.00
No (n = 721)	41.28 ± 39.07	6.57–180.00
Miscarriage			0.4495	0.4299
Yes (n = 101)	44.90 ± 34.03	7.97–180.00
No (n = 820)	42.21 ± 29.54	6.57–180.00
Live birth			0.0152	0.0179
Yes (n = 188)	47.25 ± 29.08	9.59–180.00
No (n = 733)	41.29 ± 30.20	6.57–180.00

Figure 1. Kaplan-Meier Plots of SHBG levels. Kaplan-Meier curves of event-free survival by SHBG for ovulation (A), conception(B), pregnancy (C), miscarriage (D), and live birth (E). in quartile 4 of SHBG (red line) or quartiles 1 to 3 (black line). P value assessed by log-rank test.

Data availability statement

The datasets generated analyzed during the current study are not publicly available, but are available from the corresponding author on reasonable request.