Impact of vitamin D supplementation on markers of bone turnover: Systematic review and meta-analysis of randomised controlled trials.

AIM: The effects of vitamin D administration on bone turnover markers (BTMs) in adults are controversial. Thus, we carried out a meta-analysis of available randomised controlled trials (RCTs) to examine the impact of vitamin D supplementation on BTMs. METHODS: To identify relevant RCTs, we searched the PubMed/MEDLINE, Web of Science, Scopus, Cochrane Library and Embase databases for manuscripts published up to July 2022. The present study was conducted in agreement with the PRISMA guidelines. Weighed mean difference (WMD) and 95% confidence intervals (CI) were used to calculate the magnitude of the effect of the intervention. RESULTS: A total of 42 RCTs were included in the meta-analysis. The age of the participants enrolled in the RCTs ranged from 19.4 to 84 years. The pooled results depicted a decrease in deoxypyridinoline (DPD) concentrations (WMD: -1.58 nmol/mmol, 95% CI: -2.55, -.61, p = .001) following vitamin D supplementation. In addition, subgroup analyses demonstrated that vitamin D administration notably reduced procollagen type I N-terminal propeptide (PINP) levels in individuals aged >50 years and led to a pronounced decrease in alkaline phosphatase (ALP) values when the intervention lasted >12 weeks. No significant effect was observed on other BTMs, for example, collagen type 1 cross-linked C-telopeptide (CTX) and osteocalcin (OC) levels. CONCLUSION: Vitamin D administration decreases DPD, PINP and ALP levels, indicating a reduced bone turnover following the intervention. Other BTMs, for example, CTX or OC values, were not affected by vitamin D prescription. Vitamin D supplementation may exert a positive effect on some important BTMs.

A comprehensive review and meta-regression analysis of randomized controlled trials examining the impact of vitamin B12 supplementation on homocysteine levels.

CONTEXT: Although some research suggests that vitamin B12 (hereafter, B12) supplements can lower homocysteine (Hcy) levels and treat hyperhomocysteinemia, these results are still ambiguous when B12 is taken as an isolated supplement. OBJECTIVE: This study sought to determine how existing randomized controlled trials (RCTs) could be used to examine the effects of B12 supplementation on Hcy. DATA SOURCES: To find pertinent RCTs up to June 2022, databases, including PubMed/Medline, Web of Science, Scopus, Cochrane Library, and Embase, were searched. DATA EXTRACTION: All selected RCTs investigated the impact of B12 supplements on Hcy. A meta-analysis of the eligible studies was performed using the random-effects model. DATA ANALYSIS: This review included a total of 21 RCTs (N = 1625 participants). Hcy levels were significantly lower after B12 supplementation compared with the control group (pooled weighted mean difference, -4.15 µmol/L; 95% confidence interval, -4.86, -3.45; P < 0.001), and this reduction was even greater with intervention durations ≥12 weeks and doses >500 µg/d. Furthermore, the effect of B12 supplementation in the form of hydroxocobalamin on the reduction of Hcy level was greater compared with other forms. CONCLUSION: In conclusion, this meta-analysis shows that B12 supplementation has a positive impact on lowering blood Hcy levels, particularly when administered for a longer period and at a larger dose. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42022364066.

The Effect of Anastrozole on the Lipid Profile: Systematic Review and Meta-analysis of Randomized Controlled Trials.

PURPOSE: We aimed to investigate the impact of anastrozole administration on the traditional components of the lipid profile (ie, total cholesterol [TC], LDL-C, HDL-C, and triglycerides [TGs]) by means of a systematic review and meta-analysis of randomized controlled trials. METHODS: We searched the PubMed/Medline, Scopus, Embase, and Web of Science databases for relevant randomized controlled trials published in the English language until January 18, 2022. The weighted mean difference (WMD) and 95% CIs were calculated using a random-effects model (DerSimonian and Laird methods). FINDINGS: Anastrozole administration significantly lowered TC concentrations when the treatment duration was ≤3 months (WMD = -2.73 mg/dL; 95% CI, -5.09 to -0.38 mg/dL; P = 0.02) and when the baseline TC concentration was ≥200 mg/dL (WMD = -3.64 mg/dL; 95% CI, -6.30 to -0.98 mg/dL; P = 0.007). HDL-C levels decreased after anastrozole administration when the treatment duration was >3 months (WMD = -1.67 mg/dL; 95% CI, -3.24 to -0.10 mg/dL; P = 0.03). Anastrozole administration had no impact on TG or LDL-C values. IMPLICATIONS: Anastrozole administration in humans can decrease TC and HDL-C levels but has no effect on LDL-C or TG concentrations.