Trimethyllysine Predicts All-Cause and Cardiovascular Mortality in Community-Dwelling Adults and Patients With Coronary Heart Disease

Aims Trimethyllysine (TML) is involved in carnitine synthesis, serves as a precursor of trimethylamine N-oxide (TMAO) and is associated with cardiovascular events in patients with established coronary heart disease (CHD). We prospectively examined circulating TML as a predictor of all-cause and cardiovascular mortality in community-dwelling adults and patients with CHD. Methods and Results By Cox regression modelling, risk associations were examined in 6393 subjects in the community-based Hordaland Health Study (HUSK). A replication study was conducted among 4117 patients with suspected stable angina pectoris in the Western Norway Coronary Angiography Cohort (WECAC). During a mean follow-up of 10.5 years in the HUSK-cohort, 884 (13.8%) subjects died, of whom 287 from cardiovascular causes. After multivariable adjustments for traditional cardiovascular risk factors, the hazard ratio (HR) (95% CI) for all-cause mortality comparing the 4th vs. 1st TML-quartile was 1.66 (1.31-2.10, p < 0.001). Particularly strong associations were observed for cardiovascular mortality (HR [95% CI] 2.04 [1.32-3.15, p = 0.001]). Corresponding risk-estimates in the WECAC (mean follow-up of 9.8 years) were 1.35 [1.10-1.66, p = 0.004] for all-cause and 1.45 [1.06-1.98, p = 0.02] for cardiovascular mortality. Significant correlations between plasma TML and TMAO were observed in both cohorts (rs≥0.42, p < 0.001); however, additional adjustments for TMAO did not materially influence the risk associations, and no effect modification by TMAO was found. Conclusion Elevated TML-levels were associated with increased risk of all-cause and cardiovascular mortality both in subjects with and without established CHD.