Effect of vitamin D supplementation on hormones and menstrual cycle regularization in polycystic ovary syndrome women: A systemic review and meta-analysis

Abstract

Aim: Polycystic ovary syndrome (PCOS) is a prevalent endocrine disease among women of childbearing age. Women with PCOS frequently experience reproductive complications, which are closely associated with the concentration of vitamin D. This systemic review and meta-analysis were conducted to elucidate the possible effect of vitamin D supplementation in PCOS women on hormones, including Luteinizing hormone (LH), follicle-stimulating hormone (FSH), the ratio of LH and FSH (LH/FSH), and the menstrual cycle regularization.

Methods: We searched PubMed, Web of Science, Ovid MEDLINE, Cochrane Library, and EMBASE for the relevant articles published up to January 2022. The pooled estimates were calculated using RevMan 5.4 software.

Results: Twelve studies involving 849 PCOS patients were included. Our study indicated that vitamin D supplementation could reduce serum LH (standard mean difference [SMD]: -0.41; 95% confidence interval [CI]: -0.54, -0.28; p < 0.01). Subgroup analysis identified that the supplementation of vitamin D ≤4000 IU/day (SMD: -0.69; 95% CI: -1.15, -0.23; p < 0.01), treatment time ≤8 weeks (SMD: -0.61; 95% CI: -0.95, -0.26; p < 0.01), and vitamin D co-supplementation (SMD: -0.37; 95% CI: -0.65, -0.10; p < 0.01) were related to reduce serum LH level. In addition, vitamin D supplementation improved the regularity of menstrual cycle significantly (risk ratio [RR]: 1.35; 95% CI: 1.18, 1.54; p < 0.01). In stratified analysis, the significant effects only existed in dosage of vitamin D >4000 IU (RR: 1.62; 95% CI: 1.02, 2.57; p < 0.01), treatment time >8 weeks (RR: 1.41; 95% CI: 1.06, 1.87; p = 0.02) and vitamin D co-supplementation (RR: 1.18; 95% CI: 1.03, 1.35; p = 0.02). However, vitamin D might have no effects on serum FSH (SMD: -0.05; 95% CI: -0.42, 0.32; p = 0.79) and LH/FSH (SMD: -0.24; 95% CI: -0.55, 0.08; p = 0.14) in PCOS patients.

Conclusions: Evidence from the existing randomized controlled trials indicated that vitamin D supplementation might improve the LH level and the menstrual cycle regularization but did not have any effect on FSH and LH/FSH levels in PCOS patients.

Keywords: hormone; menstrual cycle; meta-analysis; polycystic ovary syndrome; vitamin D.