RESUMO
This study aimed to review randomized controlled trials (RCTs) investigating the effects of dietary antioxidant supplements on the severity of endometriosis-related pain symptoms. The PubMed/Medline, Scopus, and Web of Science databases were searched until April 2022. Additionally, we manually searched the reference lists. Endpoints were summarized as standardized mean difference (SMD) with 95% confidence intervals (CIs) in a random-effects model. The I2 statistic was used to assess heterogeneity. Ten RCTs were included in this meta-analysis. Overall, 10 studies were related to dysmenorrhea, four to dyspareunia, and four to pelvic pain. Antioxidants significantly reduced dysmenorrhea (SMD, -0.48; 95% CI, -0.82 to -0.13; I2=75.14%). In a subgroup analysis, a significant reduction of dysmenorrhea was observed only in a subset of trials that administered vitamin D (SMD, -0.59; 95% CI, -1.13 to -0.06; I2=69.59%) and melatonin (SMD, -1.40; 95% CI, -2.47 to -0.32; I2=79.15%). Meta-analysis results also suggested that antioxidant supplementation significantly improved pelvic pain (SMD, -1.51; 95% CI, -2.74 to -0.29; I2=93.96%), although they seem not to have a significant beneficial impact on the severity of dyspareunia. Dietary antioxidant supplementation seems to beneficially impact the severity of endometriosis-related dysmenorrhea (with an emphasis on vitamin D and melatonin) and pelvic pain. However, due to the relatively small sample size and high heterogeneity, the findings should be interpreted cautiously, and the importance of further well-designed clinical studies cannot be overstated.
RESUMO
Impaired vitamin D status is highly prevalent among women with UFs. The objective of this first-ever systematic review and meta-analysis was to summarize the effect of vitamin D supplementation on the size of uterine fibroids (UFs). We performed a comprehensive literature search for published randomized controlled trials (RCTs) in Medline, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials from inception to September 2022. Five trials including 511 participants (256 cases and 255 controls) were included. Pooling results from five trials, which compared size of UFs between experimental and placebo groups, revealed that vitamin D supplementation could significantly decrease the size of UFs (standardized mean difference [SMD]: -0.48, 95% confidence interval [CI]: -0.66, -0.31) and cause improvement in serum level of vitamin D compared to placebo group (SMD: 3.1, 95% CI: 0.66, 5.55). A significant effect was observed in the subset of trials administering vitamin D supplementation for >8 wk (SMD: -0.62, 95% CI: -0.88, -0.37). In conclusion, vitamin D supplementation significantly increases serum levels of vitamin D and reduces the size of UFs. However, larger, well-designed RCTs are still needed to determine the effect of vitamin D on other parameters of UFs.