Vitamin D improves levels of hormonal, oxidative stress and inflammatory parameters in polycystic ovary syndrome: a meta-analysis study.

BACKGROUND

Hyperandrogenism (HA), inflammation, and oxidative damage play key roles in the pathophysiology of polycystic ovary syndrome (PCOS). Whether vitamin D adjuvant therapy improves hormonal, inflammation, and oxidative damage in PCOS patients has aroused widespread interest, but the results are controversial. To evaluate the effect of vitamin D supplementation on hormonal, oxidative stress, and inflammatory parameters in patients with PCOS.

METHODS

A literature search was conducted in Medline, the Cochrane Library, EMBASE, and Web of Science for studies related to PCOS and vitamin D supplementation. All reports of randomized controlled trials (RCTs) published before December 2019 were identified. The fixed-effects model or random-effects model was used to calculate pooled estimates of standardized differences in means (SMD) with 95% confidence intervals (CI).

RESULTS

A total of 956 identified studies were retrieved, and eighteen RCTs involving 1,060 participants were ultimately included in the current meta-analysis. The pooled results demonstrated that vitamin D supplementation in patients with PCOS resulted in a significant improvement in serum total testosterone (TT), high sensitivity C-reactive protein (hs-CRP), total antioxidant capacity (TAC), and malondialdehyde (MDA). No significant effect on free testosterone (FT), dehydroepiandrosterone sulfate (DHEA-S), sex hormone-binding globulin (SHBG), free androgen index (FAI), nitric oxide (NO), and total glutathione (GSH) levels was found. Subgroup analysis showed that vitamin D supplementation reduced hs-CRP and MDA irrespective of the treatment course, type of vitamin D intervention, supplementation frequency, and dosage. Twelve weeks of vitamin D supplementation improved TT and TAC while low-dose vitamin D supplementation (≤1,000 IU/day) improved TT and DHEA-S. Vitamin D co-supplementation reduced TT, FT, and DHEA-S, while a daily supplementation regime improved TT, DHEA-S, and TAC in patients with PCOS.

CONCLUSIONS

The current meta-analysis demonstrates that vitamin D supplementation in patients with PCOS resulted in an improvement in the levels of TT, hs-CRP, TAC, and MDA, but did not affect FT, DHEA-S, SHBG, FAI, NO, and GSH levels. Vitamin D co-supplementation, low-dose vitamin D supplementation (≤1,000 IU/day), and daily supplementation frequency appeared to be more conducive to improving hormones, inflammation, and oxidative stress in PCOS patients.