Yu D, et al. - In a nested case-control study, with 275 participants that have incident coronary heart disease (CHD) and 275 individually matched controls, researchers assessed the associations of urinary levels of trimethylamine-N-oxide (TMAO, a diet-derived, gut microbial-host cometabolite) and its precursor metabolites (ie, choline, betaine, and carnitine) with CHD risk among Chinese adults. A risk of CHD was reported in association with urinary TMAO, but not its precursors. After adjusting for CHD risk factors including obesity, diet, lifestyle, and metabolic diseases, 1.91 was the estimated odds ratio for the highest vs lowest quartiles of TMAO; this was reported as 1.75 after further adjusting for potential confounders or mediators including central obesity, dyslipidemia, inflammation, and intake of seafood and deep-fried meat or fish, which were found to be related to TMAO level. The link between TMAO and CHD was altered by a history of diabetes mellitus. Also, the associations of choline, betaine, and carnitine with risk of CHD were altered by diabetes mellitus status. Overall, TMAO may quicken CHD development and this implies that diet–gut microbiota–host interplay is important in cardiometabolic health.