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1.
Association Between Prediabetes and Retinopathy: A Meta-Analysis.
Jin, J, Lu, P
Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme. 2021;(12):801-809
Abstract
Diabetes confers an increased risk of microvascular complications, including retinopathy. However, whether prediabetes is also related to retinopathy has not been comprehensively examined. We performed a meta-analysis to evaluate the relationship between prediabetes and retinopathy. This meta-analysis included relevant observational studies from Medline, Embase, and Web of Science databases. A random-effect model after incorporation of the intra-study heterogeneity was selected to pool the results. Subgroup analyses were applied to evaluate the influences of study characteristics on relationship. Nine cross-sectional studies including 14 751 community dwelling adult participants were included; 3847 (26.1%) of them were prediabetic. Results showed that prediabetes was associated with a higher prevalence of retinopathy compared to normoglycemia [odds ratio (OR): 1.55, 95% confidence interval (CI): 1.10-2.20, p=0.01, I2=34%]. Sensitivity analysis by excluding one study at a time showed consistent result (OR: 1.35 to 1.73, p all<0.05). Subgroup analysis showed study characteristics such as definition of prediabetes, country of study, sample size, mean age of participants, or univariate or multivariate analyses may not significantly affect the association (p for subgroup difference all>0.05). Current evidence suggests that patients with prediabetes may be associated with higher prevalence of retinopathy as compared to those with normoglycemia. Although prospective cohort studies are needed to validate these findings, results of our meta-analysis highlighted the importance of early prevention of retinopathy in patients with prediabetes.
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Effect of Vitamin D Supplementation on the Incidence of Diabetes Mellitus.
Barbarawi, M, Zayed, Y, Barbarawi, O, Bala, A, Alabdouh, A, Gakhal, I, Rizk, F, Alkasasbeh, M, Bachuwa, G, Manson, JE
The Journal of clinical endocrinology and metabolism. 2020;(8)
Abstract
CONTEXT The effect of vitamin D supplementation on the risk of type 2 diabetes mellitus (T2DM) remains controversial because most randomized controlled trials (RCTs) have been small or have reported low doses of vitamin D. OBJECTIVE To conduct a meta-analysis of RCTs testing vitamin D supplementation in the prevention of T2DM. DATA SOURCES Database search of PubMed/MEDLINE, EMBASE, and the Cochrane Library was performed by 2 reviewers from inception through September 15, 2019. STUDY SELECTION We included RCTs that reported the effect of vitamin D supplementation for at least 1 year on T2DM prevention. DATA EXTRACTION Two independent reviewers extracted the data. The risk ratios (RRs) and 95% confidence intervals (CIs) were reported. Primary outcome of the meta-analysis was the incidence of T2DM. DATA SYNTHESIS Nine RCTs were included (43 559 participants). The mean age (standard deviation) was 63.5 (6.7) years. The RR for vitamin D compared with placebo was 0.96 (95% CI, 0.90-1.03); P = 0.30. In trials testing moderate to high doses of supplementation (≥1000 IU/day), all conducted among participants with prediabetes, the RR for vitamin D compared with placebo was 0.88 (95% CI, 0.79-0.99). In contrast, the trials testing lower doses, which were conducted in general population samples, showed no risk reduction (RR, 1.02; 95% CI, 0.94-1.10; P, interaction by dose = 0.04). CONCLUSION In patients with prediabetes, vitamin D supplementation at moderate to high doses (≥1000 IU/day), significantly reduced the incidence risk of T2DM, compared with placebo.
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3.
Zinc-alpha2-glycoprotein, dysglycaemia and insulin resistance: a systematic review and meta-analysis.
Pearsey, HM, Henson, J, Sargeant, JA, Davies, MJ, Khunti, K, Suzuki, T, Bowden-Davies, KA, Cuthbertson, DJ, Yates, TE
Reviews in endocrine & metabolic disorders. 2020;(4):569-575
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Abstract
To systematically review the current literature investigating associations between zinc-alpha2-glycoprotein (ZAG) and dysglycaemia (including type 2 diabetes (T2DM), poly-cystic-ovary syndrome (PCOS), pre-diabetes or insulin resistance). This included relationships between ZAG and continuous measures of insulin and glucose. Additionally, we performed a meta-analysis to estimate the extent that ZAG differs between individuals with or without dysglycaemia; whilst examining the potential influence of adiposity. A systematic search was performed on four databases for studies on circulating ZAG concentrations in adult human populations, comparing healthy controls to individuals with dysglycaemia. Key characteristics, including the mean ZAG concentrations (mg∙L-1), and any correlational statistics between ZAG and continuous measures of glucose, glycated haemoglobin (HbA1c) or insulin were extracted. Meta-analyses were performed to compare metabolically healthy controls to cases, and on studies that compared controls and cases considered overweight or obese (body mass index (BMI) ≥25 kg.m2). 1575 papers were identified and 14 studies (16 cohorts) were considered eligible for inclusion. Circulating ZAG was lower in individuals with dysglycaemia compared to metabolically healthy controls (-4.14 [-8.17, -0.11] mg.L-1; I2 = 98.5%; p < 0.001). When using data from only studies with overweight or obese groups with or without dysglycaemia (three studies (four cohorts); pooled n = 332), the difference in circulating ZAG was no longer significant (-0.30 [-3.67, 3.07] mg. L-1; I2 = 28.0%; p = 0.225). These data suggest that ZAG may be implicated in dysglycaemia, although there was significant heterogeneity across different studies and the mediating effect of adiposity cannot be excluded. Therefore, more research is needed before robust conclusions can be drawn.
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The effectiveness of pistachio on glycemic control and insulin sensitivity in patients with type 2 diabetes, prediabetes and metabolic syndrome: A systematic review and meta-analysis.
Nowrouzi-Sohrabi, P, Hassanipour, S, Sisakht, M, Daryabeygi-Khotbehsara, R, Savardashtaki, A, Fathalipour, M
Diabetes & metabolic syndrome. 2020;(5):1589-1595
Abstract
BACKGROUND AND AIMS Pistachio nuts have been considered to improve dysglycemia. However, there are controversial results. This systematic review and meta-analysis carried out to evaluate the effects of pistachio nuts on glycemic control and insulin sensitivity in patients with type 2 diabetes mellitus (T2DM), prediabetes, and metabolic syndrome. METHODS Medline/PubMed, ProQuest, Web of Knowledge, Scopus, Cochrane library, and ScienceDirect were systematically searched to find randomized controlled trials (RCTs). Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) checklist was used to conduct the study. RESULTS Six RCTs were included in the review. Treatment with pistachio nuts exerted a significant reduction in fasting blood glucose (FBG) level (OR = 1.7, 95% CI; 1.2-2.4, P = 0.002, I2 = 0.0%, P = 0.731) and homeostasis model assessment of insulin resistance (HOMA-IR) index (OR = 1.5, 95% CI; 1.0-2.4, P = 0.043, I2 = 0.0%, P = 0.617), but no significant improvement was observed in regard to hemoglobin A1c (HbA1c) level (OR = 1.4, 95% CI; 0.9-2.1 P = 0.089, I2 = 0.0%, P = 0.957) and fasting plasma insulin (FPI) level (OR = 1.3, 95% CI; 0.9-1.9, P = 0.133, I2 = 0.0%, P = 0.776). CONCLUSIONS Pistachio nuts might cause a significant reduction in FBG and HOMA-IR, although HbA1c and FPI might not significantly improve in patients suffering from or at risk of T2DM.
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Efficacy and safety of cinnamon in type 2 diabetes mellitus and pre-diabetes patients: A meta-analysis and meta-regression.
Deyno, S, Eneyew, K, Seyfe, S, Tuyiringire, N, Peter, EL, Muluye, RA, Tolo, CU, Ogwang, PE
Diabetes research and clinical practice. 2019;:107815
Abstract
INTRODUCTION Cinnamon has been used as a dietary component and in the management of diabetes mellitus. This study systematically reviewed and synthesized evidence on the efficacy of cinnamon for the treatment of type 2 diabetes mellitus (T2DM) and pre-diabetes patients. METHODS Databases of Web of Sciences, the Cochrane library, PubMed, CINAHL and SCOPUS were searched. Stata version 13 (College Station, Texas 77845 USA) and RevMan var. 5.3 software were used for meta-analysis. Heterogeneity was assessed using Chi-square and I2 tests. RESULTS Sixteen randomized controlled studies were included in the meta-analysis. Cinnamon significantly reduced fasting blood glucose (FBG) and homeostatic model assessment for insulin resistance (HOMA-IR) level compared to placebo with weighted mean difference (WMD) of -0.545 (95% CI: -0.910, -0.18) mmol/L, I2 = 83.6% and -0.714(-1.388, -0.04), I2 = 84.4% respectively. There was no significant change in weighted mean difference of glycosylated hemoglobin A1C (HbA1c) % and lipid profiles (mmol/L). Meta-regression did not show any factor significantly affecting the treatment response. CONCLUSION Cinnamon reduced FBG and HOMA-IR, level in T2DM and pre-diabetes patients compared to placebo. High heterogeneity observed among included studies warrants further clinical trials after standardization of cinnamon formulation.
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Evidence and potential mechanisms of traditional Chinese medicine for the treatment of type 2 diabetes: A systematic review and meta-analysis.
Tian, J, Jin, D, Bao, Q, Ding, Q, Zhang, H, Gao, Z, Song, J, Lian, F, Tong, X
Diabetes, obesity & metabolism. 2019;(8):1801-1816
Abstract
Traditional Chinese medicine (TCM) has recorded knowledge of diabetes for over 2000 years. Because a considerable number of TCM studies exhibit design defects, such as limited intervention duration, small sample sizes and inconsistent efficacy evaluations, the role of TCM in the treatment of diabetes cannot be fully elucidated. In this review, we evaluate randomized controlled trials of prediabetes, diabetes and diabetic complications published in the past decade. We found that TCM could significantly improve glucose control and clinical indices in patients with diabetes and effectively delay the progression of diabetes. We also summarize potential pharmacological mechanisms underlying the efficacy of TCM medication/herbs and their active ingredients for treating diabetes. More rigorously designed experiments and long-term evaluation of TCM for diabetes will allow for more effective diabetes management.
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Comparing different definitions of prediabetes with subsequent risk of diabetes: an individual participant data meta-analysis involving 76 513 individuals and 8208 cases of incident diabetes.
Lee, CMY, Colagiuri, S, Woodward, M, Gregg, EW, Adams, R, Azizi, F, Gabriel, R, Gill, TK, Gonzalez, C, Hodge, A, et al
BMJ open diabetes research & care. 2019;(1):e000794
Abstract
OBJECTIVE There are currently five widely used definition of prediabetes. We compared the ability of these to predict 5-year conversion to diabetes and investigated whether there were other cut-points identifying risk of progression to diabetes that may be more useful. RESEARCH DESIGN AND METHODS We conducted an individual participant meta-analysis using longitudinal data included in the Obesity, Diabetes and Cardiovascular Disease Collaboration. Cox regression models were used to obtain study-specific HRs for incident diabetes associated with each prediabetes definition. Harrell's C-statistics were used to estimate how well each prediabetes definition discriminated 5-year risk of diabetes. Spline and receiver operating characteristic curve (ROC) analyses were used to identify alternative cut-points. RESULTS Sixteen studies, with 76 513 participants and 8208 incident diabetes cases, were available. Compared with normoglycemia, current prediabetes definitions were associated with four to eight times higher diabetes risk (HRs (95% CIs): 3.78 (3.11 to 4.60) to 8.36 (4.88 to 14.33)) and all definitions discriminated 5-year diabetes risk with good accuracy (C-statistics 0.79-0.81). Cut-points identified through spline analysis were fasting plasma glucose (FPG) 5.1 mmol/L and glycated hemoglobin (HbA1c) 5.0% (31 mmol/mol) and cut-points identified through ROC analysis were FPG 5.6 mmol/L, 2-hour postload glucose 7.0 mmol/L and HbA1c 5.6% (38 mmol/mol). CONCLUSIONS In terms of identifying individuals at greatest risk of developing diabetes within 5 years, using prediabetes definitions that have lower values produced non-significant gain. Therefore, deciding which definition to use will ultimately depend on the goal for identifying individuals at risk of diabetes.
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8.
Effect of Vitamin K Supplementation on Glycemic Control: A Systematic Review and Meta-Analysis of Clinical Trials.
Shahdadian, F, Mohammadi, H, Rouhani, MH
Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme. 2018;(3):227-235
Abstract
Type 2 diabetes mellitus (T2DM) is one of the most important public health issues. Vitamin K supplementation might have favorable effect on risk factors of T2DM. The aim of this study was to perform a systematic review and meta-analysis of interventional studies to examine the effect of vitamin K supplementation on glycemic indices. A systematic search was performed in electronic databases including PubMed, Science Direct, ProQuest, Institute of Scientific Information Web of Science, and Google scholar up to July 2017. We used a random effects model to estimate pooled effect size of fasting blood sugar (FBS), 2-h oral glucose tolerance test (2-h OGTT), fasting insulin (FINS), and homeostasis model assessment-estimated insulin resistance (HOMA-IR). Five clinical trials (533 participants) fulfilled the eligibility criteria of the present meta-analysis. Overall, meta-analysis could not show any beneficial effect of vitamin K supplementation on FBS (-0.91 mg/dl, 95% CI: -2.57, 0.76, p=0.28), FINS (-0.35 μIU/ml, 95% CI: -1.70, 1.00, p=0.61), HOMA-IR (-0.06, 95% CI: -0.32, -0.19, p=0.63), and 2-h OGTT (-4.00 mg/dl, 95% CI: -20.00, 11.99, p=0.62). Sensitivity analysis showed that overall estimates were not affected by elimination of any study. We did not observe any evidence regarding publication bias. In conclusion, vitamin K supplementation had no significant effect on glycemic control in healthy subjects. However, further studies should be performed on diabetic and pre-diabetic patients to determine the effect of vitamin K supplementation on impaired glycemic control.
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Efficacy of Aloe Vera Supplementation on Prediabetes and Early Non-Treated Diabetic Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Zhang, Y, Liu, W, Liu, D, Zhao, T, Tian, H
Nutrients. 2016;(7)
Abstract
The aim of this study was to evaluate evidence for the efficacy of aloe vera on managing prediabetes and early non-treated diabetes mellitus. We performed a systematic search of PubMed, Embase, and Cochrane Central Register of Controlled Trials until 28 January 2016. A total of five randomized controlled trials (RCTs) involving 415 participants were included. Compared with the controls, aloe vera supplementation significantly reduced the concentrations of fasting blood glucose (FBG) (p = 0.02; weighed mean difference [WMD]: -30.05 mg/dL; 95% confidence interval [CI]: -54.87 to -5.23 mg/dL), glycosylated hemoglobin A1c (HbA1c) (p < 0.00001; WMD: -0.41%; 95% CI: -0.55% to -0.27%), triglyceride (p = 0.0001), total cholesterol (TC) (p < 0.00001), and low density lipoprotein-cholesterol (LDL-C) (p < 0.00001). Aloe vera was superior to placebo in increasing serum high density lipoprotein-cholesterol (HDL-C) levels (p = 0.04). Only one adverse event was reported. The evidence from RCTs showed that aloe vera might effectively reduce the levels of FBG, HbA1c, triglyceride, TC and LDL-C, and increase the levels of HDL-C on prediabetes and early non-treated diabetic patients. Limited evidence exists about the safety of aloe vera. Given the small number and poor quality of RCTs included in the meta-analysis, these results are inconclusive. A large-scale, well-designed RCT is needed to further address this issue.
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10.
Which diet for prevention of type 2 diabetes? A meta-analysis of prospective studies.
Esposito, K, Chiodini, P, Maiorino, MI, Bellastella, G, Panagiotakos, D, Giugliano, D
Endocrine. 2014;(1):107-16
Abstract
No specific diet is recommended to prevent type 2 diabetes. We did a meta-analysis of prospective cohort studies to assess the association between different diets and prevention of type 2 diabetes. We did a comprehensive search of multiple electronic databases (Medline, Scopus, EMBASE, and ISI web of knowledge) until August 2013 using predefined criteria. We included prospective cohort studies that evaluated the role of different diets in type 2 diabetes prevention. Studies were selected by 2 independent reviewers. We did random-effects meta-analyses to determine the relative risk (RR) of incident diabetes associated with healthful dietary patterns. A total of 21,372 cases of incident diabetes, from 18 prospective studies, with 20 cohorts, in 4 world regions were identified. In the random-effect meta-analysis of the 20 cohorts, RR was 0.80 (95 % confidence interval (CI) = 0.74-0.86, P < 0.001), with high heterogeneity (I (2) = 57 %, P = 0.001) and no evidence of publication bias (Egger's test, P = 0.653). Exclusion of two cohorts produced identical RR (0.80, 95 % CI 0.76-0.84), with nonsignificant heterogeneity (I (2) = 9 %). The risk of incident diabetes did not appreciably change considering the geography (USA, Europe, and Asia), the duration of follow-up (≤10 and >10 years), and type of diets (Mediterranean and DASH, Dietary Approaches to Stop Hypertension, diets). There was a difference between at risk and general population (P = 0.0487), but the evidence was limited to two studies only. The results of our study demonstrate that several healthy diets are equally and consistently associated with a 20 % reduced risk of future type 2 diabetes.