| Objective The effects of vitamin D on endocrine,metabolic and oxidative stress indexes of polycystic ovary syndrome were systematically evaluated through meta-analysis,so as to provide more effective treatment for patients with polycystic ovary syndrome,improve clinical symptoms and reduce pain of patients,and also provide a strong reference for clinicians to assist patients with treatment.Methods 1.Search China National Knowledge Infrastructure(CNKI),Wanfang Database,VIP Database for Chinese Technical Periodicals(VIP),the Chinese Biological Medicine Database(CBM),PubMed,Embase,Web of science,Cochrane Library and other databasesby computer to collect a randomized controlled study of the effects of vitamin D on endocrine,metabolic and oxidative stress-related indexes in polycystic ovary syndrome.2.Search strategy:First,the question is transformed into PICOS mode,the search strategy is determined,and then the combination of subject words and free words is selected for search.At the same time,the reference literature is searched and the relevant literature is supplemented.Search time:from the establishment of each database to June 2022.Search language:Chinese,English.3.Evaluation of literature quality:According to the established inclusion criteria and exclusion criteria,two researchers started literature screening and content extraction respectively.At the same time,according to the"bias risk assessment"tool,the quality of the included literature was evaluated and checked with each other.If there are differences,they can be discussed and resolved by the third researcher.4.RevMan 5.4 software,a special software for systematic review of Cochrane Collaboration network,was used to evaluate literature quality,and Stata 16.0 software was used to analyze data.Normalized mean difference(SMD)and 95%confidence interval(CI)were calculated for all outcome measures.If P≥0.1 and I~2≤50%,the heterogeneity of the included studies was small.The fixed effect model was used to calculate the combined statistics,if P<0.1,I~2>50%,indicating high heterogeneity of the included studies.The random effect model was used to calculate the combined statistics.Subgroup analyses were performed to assess the dose of vitamin D(≥4000IU/d or<4000IU/d),intervention duration(≥12 weeks or<12 weeks)on endocrine,metabolic and oxidative stress related indexes in PCOS patients.(The meta-analysis test level was set atα=0.05).Results 1.A total of 766 relevant literatures were preliminarily retrieved,duplicate literatures were excluded,and irrelevant literatures were excluded after reading the title and abstract.After reading the full text,a total of 14 randomized controlled trial literatures were included in the study,including 2 Chinese literatures and 12 English literatures,with a total of 902PCOS patients,476 in the vitamin D group and 426 in the placebo group.2.The Meta-analysis results showed that:2.1Endocrine index:Compared with placebo group,total testosterone(TT)and parathyroid hormone(PTH)levels of PCOS patients in vitamin D group were significantly decreased(P<0.05).There were no significant changes in sex hormone-binding globulin(SHBG),dehydroepiandrosterone sulfate(DHEAS),quantitative insulin sensitivity check index(QUICKI)and insulin resistance index(HOMA-IR)(P>0.05).In PCOS patients supplemented with high dose vitamin D(≥4000IU/d)or supplemented for≥12 weeks,TT,PTH concentration and HOMA-IR were significantly decreased,while SHBG was significantly increased(P<0.05),and there was no significant difference in the remaining indexes(QUICKI and DHEAS)(P>0.05).2.2metabolic index:Compared with placebo,supplementation significantly increased serum vitamin D concentration and decreased triglyceride(TG)and low-density lipoprotein(LDL)levels(P<0.05),but the levels of total cholesterol(TC),but high density lipoprotein(HDL)was not significantly different from those of placebo group(P>0.05).The concentrations of TC,TG and LDL in PCOS patients supplemented with high dose vitamin D(≥4000IU/d)or supplemented for≥12 weeks were significantly decreased(P<0.05),there were no significant differences in HDL levels(P>0.05).2.3Oxidative stress index:Compared with placebo group,vitamin D supplementation increased glutathione(GSH)level and decreased malondialdehyde(MDA)level in PCOS patients(P<0.05),but NO and total antioxidant capacity in PCOS patients were not significantly changed(P>0.05).Conclusion 1.Vitamin D supplementation can improve the levels of hyperandrogen,abnormal lipid metabolism and oxidative stress in PCOS patients to a certain extent.2.Supplementation of high dose vitamin D(≥4000IU/d)for≥12 weeks seems to be more beneficial to hyperandrogen,lipid metabolism and insulin resistance in PCOS patients. |
