Trimethylamine-N-oxide levels linked to stroke risk

The gut microbiota-derived metabolite trimethylamine-N-oxide (TMAO) is significantly associated with the risk of stroke, according to a study.

Specifically, higher TMAO levels resulted in a higher stroke risk, and stroke patients present with higher mean TMAO concentrations. High TMAO plasma levels also independently predict major adverse cardiovascular events (MACEs) and all-cause mortality.

In this systematic review and meta-analysis, the investigators searched the databases of PubMed, Embase, Cochrane Library, and Web of Science from 1 January 2001 to 1 June 2021 for studies examining the relationship between TMAO and stroke. A total of 30,808 participants from eligible studies were included in the meta-analysis.

Results showed that higher TMAO category increased the chances of having a stroke by as much as 68 percent (odds ratio [OR], 1.83, 95 percent confidence interval [CI], 1.02‒3.29; p=0.04). Notably, stroke patients had 2.20-μmol/L (95 percent CI, 1.23‒3.16; p<0.00001) higher mean TMAO concentrations than nonstroke controls.

Higher TMAO plasma levels also contributed to the increased risk of all-cause mortality (hazard ratio, 1.89, 95 percent CI, 1.15‒3.08; p=0.01).

On both univariate and multivariate analyses, high TMAO levels were significantly associated with a greater risk of MACEs (univariate: pooled risk ratio [RR], 2.26, 95 percent CI, 2.01‒2.54; p<0.00001; multivariate: pooled RR, 1.55, 95 percent CI, 1.17‒2.05; p=0.002).