Objective: To investigate whether serum 25-hydroxyvitamin D [25(OH)D] level is associated with ovarian reserve markers in secondary amenorrhea (SA) patients.
Methods: Sixty-three women diagnosed with SA were recruited during 12 months from the initiation of this prospective observational study. Serum 25(OH)D levels, serum anti-Müllerian hormone (AMH) levels and antral follicle count (AFC) were estimated in study participants and ovarian reserve markers were compared between participants with vitamin D deficiency and those with normal vitamin D levels.
Results: Of the 63 participants, 27 (42.9%) were vitamin D deficient (<20 ng/mL) and 36 (57.1%) had normal vitamin D levels. The mean AMH levels and AFC were 10.86±8.94 µ/L and 15.23±7.65 in the vitamin D deficient group, and 7.24±5.62 µ/L and 12.30±6.95 in the normal vitamin D group. Univariate and multivariate linear regression analysis of log10 transformed AMH and AFC with serum 25(OH)D adjusted for age and body mass index confirmed no association between vitamin D levels and AMH levels or AFC. There was also no correlation between serum 25(OH)D and AMH levels or AFC in all participants. However, participants with vitamin D deficiency had an increased chance of having polycystic ovarian syndrome (PCOS) as cause of SA than those with normal vitamin D levels (adjusted odds ratio, 7.559; 95% confidence interval, 1.28-44.65; P=0.026) after adjustment for clinical factors by logistic regression model.
Conclusion: There was no correlation between serum 25(OH)D levels and ovarian reserve markers in SA patients, but vitamin D deficiency may be linked to PCOS patients.
Keywords: 25-hydroxyvitamin D; Amenorrhea; Anti-Mullerian hormone; Ovarian reserve; Polycystic ovarian syndrome.