The association between circulating fetuin-A levels and type 2 diabetes mellitus risk: systematic review and meta-analysis of observational studies.

BACKGROUND AND OBJECTIVE: Fetuin-A is a liver-derived circulating protein that is associated with insulin resistance and diabetes. The objective of this systematic review and meta-analysis of published observational studies was to investigate mean levels of fetuin-A in T2D patients and the relationship between blood fetuin-A levels and T2D risk. MATERIALS AND METHODS: PubMed, Embase, Google Scholar, Web of Science, and The Cochrane Library were systematically searched for potential relevant studies up to 1 December 2016. Natural logarithm-transformed estimate risks, standard mean differences on the basis of Hedges's adjusted g, and 95% confidence intervals (CIs) were calculated for all eligible studies and were combined to measure the pooled data using random-effects model. RESULTS: A total of 32 studies including 27 case-control and 5 cohort studies were included in the current study. Fetuin-A levels in T2D patients were significantly higher than control groups [Hedges' g = 1.73, 95% CI (1.25-2.22), P < 0.001], with significant heterogeneity across studies (P < 0.001, I 2 = 98.46%). Findings from meta-analyses of cohort studies showed a statistically significant association between fetuin-A levels and T2D risk [rate ratio = 1.62, 95% CI (1.26-2.08), P < 0.001], with no significant heterogeneity (P = 0.10, I 2 = 46.06%). CONCLUSION: We found a significant relationship between the fetuin-A levels with T2D risk. Although fetuin-A may be as a potential screening and prediction biomarker or a therapeutic target in T2D patients, further studies are required in this regard.

Rice Bran Oil Decreases Total and LDL Cholesterol in Humans: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials.

Cardiovascular disease (CVD) has become a concerning health problem because of its increasing prevalence. Vegetable oils such as rice bran oil may improve blood lipids, risk factors for CVD. We performed a systematic review and meta-analysis to identify and quantify the effects of rice bran oil on lipid profiles in humans. Literature databases (Pubmed, Scopus, Science Direct, Proquest, Ovid, and Google Scholar) were systematically searched until the end of November 2015, with no restrictions regarding study design, time, or language. The variables extracted for the meta-analysis included low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), total cholesterol (TC), triacylglycerol (TAG), VLDL-C, apoA, apoB, Lp(a), TC/HDL-C, and LDL-C/HDL-C. From 415 identified articles, 11 randomized controlled trials met the eligibility criteria and were included in our review. Rice bran oil consumption resulted in a significant decrease in concentrations of LDL-C (-6.91 mg/dl, 95% CI, -10.24 to -3.57; p<0.001) and TC (-12.65 mg/dl; 95% CI, -18.04 to -7.27; p<0.001). The increase in HDL-C levels were considerable only in men (6.65 mg/dl; 95% CI, 2.38-10.92; p=0.002). Results of our meta-analysis provided no evidence of a significant effekt of rice bran oil on other lipid profile components. In conclusion, consumption of rice bran oil can reduce LDL-C and TC concentrations, which may lead to prevention and control of CVD. It also has favorable effects on HDL-C concentrations in men. However, changes related to other lipid profile components are not considerable.

The Impact of a Low Glycemic Index Diet on Inflammatory Markers and Serum Adiponectin Concentration in Adolescent Overweight and Obese Girls: A Randomized Clinical Trial.

Although the effects of dietary glycemic index (GI) on insulin resistance are well documented in adults, the complex interaction among glucose intolerance, inflammatory markers, and adipokine concentration has not been well studied, especially among adolescents. We investigated the effect of a low glycemic index (LGI) diet on insulin concentration, fasting blood sugar (FBS), inflammatory markers, and serum adiponectin concentration among healthy obese/overweight adolescent females. In this parallel randomized clinical trial, 2 different diets, an LGI diet and a healthy nutritional recommendation diet (HNRD) with similar macronutrient composition were prescribed to 50 obese and overweight adolescent girls with the same pubertal status. Biochemical markers FBS, serum insulin concentration, high sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), and adiponectin were measured before and after a 10 week intervention. Using an intention-to-treat analysis, data from 50 subjects were analyzed. According to a dietary assessment, GI in the LGI group was 43.22±0.54. While the mean for FBS, serum insulin concentration, the homeostasis model assessment (HOMA), the quantitative insulin sensitivity check index (QUICKI), and adiponectin concentration did not differ significantly within each group, the average hs-CRP and IL-6 decreased significantly in the LGI diet group after the 10 week intervention (p=0.009 and p=0.001; respectively). Comparing percent changes, we found a marginally significant decrease in hs-CRP in the LGI group compared with the HNRD group after adjusting for confounders. Compliance with an LGI diet may have favorable effect on inflammation among overweight and obese adolescent girls.

Is there a relationship between red or processed meat intake and obesity? A systematic review and meta-analysis of observational studies.

A body of literature exists regarding the association of red and processed meats with obesity; however, the nature and extent of this relation has not been clearly established. The aim of this study is to conduct a systematic review and meta-analysis of the relationship between red and processed meat intake and obesity. We searched multiple electronic databases for observational studies on the relationship between red and processed meat intake and obesity published until July 2013. Odds ratios (ORs) and means for obesity-related indices and for variables that may contribute to heterogeneity were calculated. A systematic review and a meta-analysis were conducted with 21 and 18 studies, respectively (n = 1,135,661). The meta-analysis (n = 113,477) showed that consumption of higher quantities of red and processed meats was a risk factor for obesity (OR: 1.37; 95% CI: 1.14-1.64). Pooled mean body mass index (BMI) and waist circumference (WC) trends showed that in comparison to those in the lowest ntile, subjects in the highest ntile of red and processed meat consumption had higher BMI (mean difference: 1.37; 95% CI: 0.90-1.84 for red meat; mean difference: 1.32; 95% CI: 0.64-2.00 for processed meat) and WC (mean difference: 2.79; 95% CI: 1.86-3.70 for red meat; mean difference: 2.77; 95% CI: 1.87-2.66 for processed meat). The current analysis revealed that red and processed meat intake is directly associated with risk of obesity, and higher BMI and WC. However, the heterogeneity among studies is significant. These findings suggest a decrease in red and processed meat intake.