1.
Vitamin D and liver cancer risk: A meta-analysis of prospective studies.
Guo, XF, Zhao, T, Han, JM, Li, S, Li, D
Asia Pacific journal of clinical nutrition. 2020;(1):175-182
Abstract
BACKGROUND AND OBJECTIVES The association between circulating vitamin D and liver cancer risk has been controversial on the basis of epidemiological studies. The aim of this study was to quantitatively evaluate this association with prospective studies. METHODS AND STUDY DESIGN A systematic literature search was implemented in PubMed and Scopus databases up to June 2019. Using a random-effects model, the multivariate-adjusted relative risks (RRs) with corresponding 95% confidence interval (CI) were pooled for the highest versus lowest category. Trend estimation was conducted with a two-stage dose-response meta-analysis. RESULTS Six independent prospective studies (992 liver cancer events and 60,811 participants) were included for data synthesis. The summary estimate showed that a higher circulating vitamin D was associated with lower risk of liver cancer (Summary RR=0.78; 95% CI: 0.63, 0.95; I2=53.6%, p=0.035). Dose-response analysis indicated that liver cancer was associated with 8% (95% CI: 0.89, 0.95) lower risk with a 10 nmol/L increment of circulating vitamin D concentration. CONCLUSIONS The present study provides substantial evidence that a higher concentration of circulating vitamin D would have conferred protection against liver cancer.
2.
Vitamin D and non-alcoholic fatty liver disease: a meta-analysis of randomized controlled trials.
Guo, XF, Wang, C, Yang, T, Li, S, Li, KL, Li, D
Food & function. 2020;(9):7389-7399
Abstract
The results of randomized controlled trials (RCTs) investigating supplemental vitamin D on aminotransferases and cardio-metabolic risk factors in subjects with non-alcoholic fatty liver disease (NAFLD) have been inconsistent. The present study aimed to quantitatively evaluate whether supplementation with vitamin D has beneficial effects in treatment of NAFLD. A systematical literature search was performed with Cochrane Library, PubMed, Scopus databases and Web of Science up to June 2020. The mean changes in alanine aminotransferase (ALT), aspartate aminotransferase (AST), fasting glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and triglyceride (TAG) were calculated as standard mean difference (SMD) using a random-effects model. Pre-specified subgroup and univariate meta-regression analyses were performed to identify the sources of heterogeneity. Ten trials with a total of 544 NAFLD subjects were included for data synthesis. The summary estimates indicated that supplemental vitamin D significantly reduced the levels of serum/plasma fasting glucose (-0.22; 95%CI: -0.39, -0.04), insulin (-0.68; 95%CI: -1.22, -0.14) and HOMA-IR (-1.32; 95%CI: -2.30, -0.34), and marginally reduced the ALT (-0.18; 95%CI: -0.39, 0.04) and TAG (-10.38; 95%CI: -21.09, 0.34) levels. However, the pooled effect did not support that supplemental vitamin D was beneficial for concentrations of AST, TC, HDL-C and LDL-C. The present study provides substantial evidence that supplemental vitamin D has favorable effects on glycemic control and insulin sensitivity in NAFLD patients. Vitamin D could be as an adjuvant pharmacotherapy of NAFLD.
3.
The Effects of Dietary Calcium Supplements Alone or With Vitamin D on Cholesterol Metabolism: A Meta-Analysis of Randomized Controlled Trials.
Chen, C, Ge, S, Li, S, Wu, L, Liu, T, Li, C
The Journal of cardiovascular nursing. 2017;(5):496-506
Abstract
BACKGROUND Evidence supports the role of lifestyle interventions as a primary intervention strategy among individuals with dyslipidemia. The role of micronutrients, and calcium in particular, on cholesterol metabolism is not clear and warrants further investigation. OBJECTIVE The aim of this study is to conduct a meta-analysis of controlled clinical trials that have examined the effects of calcium supplements on blood lipids among adults. METHODS MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials databases were searched up to March 2016 for calcium supplements clinical trials. Other trials were selected from searching bibliography of reviews, meta-analysis, and included trials. Clinical trials with random allocation to calcium supplementation or calcium plus vitamin D supplementation, or control were selected. Data collected included study design, participant characteristics, information of the intervention, and outcomes. Data synthesis was conducted using random effect models. RESULTS A total of 22 trials, representing 4071 participants, met the eligibility criteria. Compared with control group, calcium supplements significantly reduced low-density lipoprotein cholesterol level by -0.12 mmol/L (95% confidence interval, -0.22 to -0.02) and increased high-density lipoprotein cholesterol level by 0.05 mmol/L (95% confidence interval, 0.00 to 0.10). Subgroup analyses revealed that the associations were consistent across study duration and vitamin D cosupplementation status. CONCLUSIONS Calcium supplementation has beneficial effect on blood lipids. Such supplements may be useful as a nonpharmaceutical strategy in cholesterol control.