Department of Biochemistry and Nutrition, School of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
Research Center for Evidence Based Medicine, Health Management and Safety Promotion Research Institute, Tabriz University of Medical Sciences, Tabriz, Iran.
Obes Rev. 2020 May;21(5):e12993. doi: 10.1111/obr.12993. Epub 2020 Feb 3.
It has been suggested that trimethylamine N-oxide (TMAO) is associated with increased risk of diabetes and cardiovascular disease (CVD) morbidity and mortality. However, it is not known whether increased TMAO concentrations is associated with obesity. In the current study, we summarized the evidence related to the association of circulating TMAO with the risk of obesity measurements, including body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) in a two-class and dose-response meta-analysis of observational studies. A systematic search carried out in PubMed, SCOPUS, Cochrane, and ProQuest through September 30, 2019 resulted in 12 eligible studies which were included in the current meta-synthesis. In these studies, BMI was reported but there were no reports of WC or WHR. Meta-analysis of two-class variables and dose-response meta-analysis of continuous variables were performed. Subgroup analysis and meta-regression were also performed to identify the source of heterogeneity. There was a dose-response association between circulating TMAO concentration and increased BMI in studies involving healthy individuals (P nonlinearity = .007), while no evidence of departure from linearity was observed according to study design or among patients with CVD. Results showed the highest category of TMAO was associated with 0.56 kg/m increase in BMI (weighted mean difference [WMD], 0.563; CI, 0.026-1.100; P = .04). The results of the current meta-analysis revealed a positive association between circulating TMAO and obesity as presented by increased BMI. Moreover, a dose-dependent association between circulating TMAO and obesity was also identified in apparently healthy individuals. This is the first meta-analysis to reveal positive dose-dependent associations between circulating TMAO concentration and obesity.
有人认为，三甲胺 N-氧化物（TMAO）与糖尿病和心血管疾病（CVD）发病率和死亡率的增加有关。然而，目前尚不清楚 TMAO 浓度的增加是否与肥胖有关。在本研究中，我们对观察性研究的两分类和剂量-反应荟萃分析进行了总结，以评估循环 TMAO 与肥胖测量指标（包括体重指数[BMI]、腰围[WC]和腰臀比[WHR]）风险之间的关联的证据。通过在 PubMed、SCOPUS、Cochrane 和 ProQuest 中进行系统检索，截至 2019 年 9 月 30 日，共纳入了 12 项符合条件的研究，这些研究均纳入了本次荟萃分析。在这些研究中，报告了 BMI，但没有 WC 或 WHR 的报告。对两分类变量进行了荟萃分析，对连续变量进行了剂量-反应荟萃分析。还进行了亚组分析和荟萃回归分析，以确定异质性的来源。在涉及健康个体的研究中，循环 TMAO 浓度与 BMI 增加之间存在剂量-反应关联（非线性 P 值=.007），而根据研究设计或 CVD 患者，没有观察到线性偏离的证据。结果表明，TMAO 的最高类别与 BMI 增加 0.56kg/m 相关（加权均数差[WMD]，0.563；CI，0.026-1.100；P=.04）。本荟萃分析的结果表明，循环 TMAO 与肥胖之间存在正相关，表现为 BMI 增加。此外，在明显健康的个体中也发现了循环 TMAO 与肥胖之间的剂量依赖性关联。这是首次揭示循环 TMAO 浓度与肥胖之间存在正相关且呈剂量依赖性的荟萃分析。
