Gut microbiota-dependent trimethylamine N-oxide and all-cause mortality: Findings from an updated systematic review and meta-analysis.

The gut microbiota-derived metabolite trimethylamine N-oxide (TMAO) has been regarded as one of the potent risk factors for cardiovascular events and diabetes. In the current meta-analysis we quantitatively summarized and updated the results of studies regarding the association between TMAO and mortality. A systematic search was performed from PubMed, ProQuest, Scopus, and Embase. All of the studies that evaluated the association between TMAO and mortality were included in the systematic review and meta-analysis. Subgroup analysis and meta-regression were performed to identify the source of heterogeneity. There were 31 230 participants included and the results showed that being in the highest category of TMAO increased the hazard ratio (HR) of mortality by 47%. Moreover, there was a non-linear association between increased TMAO concentrations and HR of mortality. In the current dose-response meta-analysis, we revealed a positive association between TMAO and mortality risk among an adult population.