Calcium supplementation in colorectal cancer prevention: A systematic meta-analysis of adverse events

Despite the multiple systematic reviews and meta-analyses accumulating evidence on the preventive effect of calcium supplementation for colorectal cancer, most of the associated adverse effects are not systematically analyzed. The aim of the study is evaluating adverse events associated with calcium supplementation for colorectal cancer prevention through a systematic meta-analysis. We searched Medline, PubMed Central, EMBASE (Excerpta Medica database), Scopus, Cochrane Central Register of Controlled Trials, and Web of Science published in English from database inception up to 31 July 2019. In the current systematic meta-analysis, we included human studies (including cohort studies, clinical trials, case-control studies) on supplementation of calcium in patients with or at risk of colorectal cancer. Assessment of the quality of included studies was performed by Jadad score. Information on the patient population, number of enrolled subjects in each group, dose of calcium supplementation, duration of calcium supplementation, and reported adverse events were gathered. The data were pooled for incidence rates for any adverse event during the study period regardless of causality association. We identified 6 studies, comprising 4583 participants that met the inclusion criteria. Meta-analysis on pooled incidence rates for adverse event during study period showed no statistically significant increased risk for cancer (OR = 0.92, 95% CI: 0.70–1.21, P = 0.577; I² = 0.0%, P = 0.731), coronary revascularization (OR = 1.12, 95% CI: 0.79–1.59, P = 0.492; I² = 0.0%, P = 0.957), myocardial infarction (OR = 0.81, 95% CI: 0.34–1.91, P = 0.634; I² = 67.9%, P = 0.047), stroke (OR = 0.75, 95% CI: 0.42–1.33, P = 0.332, I² = 0.00%, P = 0.717), Transient Ischemic Attack (TIA) (OR = 1.37, 95% CI: 0.28–6.51, P = 0.692, I² = 81.9%, P = 0.002), urolithiasis (OR = 1.23, 95% CI: 0.75–2.01, P = 0.410; I² = 0.0%, P = 0.851), fracture (OR = 0.98, 95% CI: 0.70–1.37, P = 0.938; I² = 37.8%, P = 0.152) and death (OR = 1.05, 95% CI: 0.71–1.56, P = 0.786, I² = 12.2%, P = 0.317) in patients receiving calcium supplementation for colorectal cancer prevention compared to control. Based on the results of Egger test, publication bias was not observed among the studies (P = 0.262). The current result of the meta-analysis on human studies reporting adverse events associated with calcium supplementation for the prevention of colorectal cancer demonstrated no statistically significant increased risk for the development of adverse events compared to control groups.     

Synthesis,characterization and evaluation of bioactivity and antibacterial activity of quinary glass system (SiO2–CaO–P2O5–MgO–ZnO): In vitro study

Bioactive glasses in the systems SiO₂–CaO–P₂O₅–MgO (BGZn0) and SiO₂–CaO–P₂O₅–MgO–ZnO (BGZn5), were prepared by sol–gel method and then characterized. Surface reactivity was studied in simulated body fluid (SBF) to determine the effect of zinc (Zn) addition as a trace element. The effect of Zn addition to the glass matrix on the formation of apatite layer on the glass surface was investigated through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT–IR) and scanning electron microscopy (SEM). Also, inductively coupled plasma–optical emission spectroscopy (ICP–sOES) was used to determine the concentrations of released ions in SBF solution after different time intervals in SBF solution. The antibacterial activity of Zn containing glass against Pseudomonas aeruginosa was measured by the halo zone test. The presence of Zn in glass composition improved chemical durability, slowed down the formation rate of Ca–P layer and decreased the size of crystalline apatite particles. Zn containing glass exhibited an excellent antibacterial activity against P. aeruginosa which could demonstrate its ability to treat bone infection.