Elevated Circulating Trimethylamine N-Oxide Levels Linked to AAA Risk, Growth Rate

WEDNESDAY, Aug. 27, 2025 (HealthDay News) — Elevated circulating trimethylamine N-oxide (TMAO) levels are associated with an increased risk for abdominal aortic aneurysms (AAA) and with the risk for fast-growing AAA, according to a study published online Aug. 20 in JAMA Cardiology.

Scott J. Cameron, M.D., Ph.D., from the Cleveland Clinic, and colleagues examined whether TMAO is associated with risk for AAA development, rapid AAA expansion, and risk for recommended surgical intervention in a prospective cohort study using two independent clinical cohorts undergoing aorta imaging surveillance. The European cohort included 237 individuals, and the U.S. cohort included 658 individuals.

The researchers found that elevated circulating TMAO was significantly associated with AAA risk in the European cohort, independent of traditional risk factors and kidney function. Elevated TMAO also predicted a greater risk for fast-growing AAA and recommended surgical intervention (adjusted odds ratios [aORs], 2.75 and 2.67, respectively). In the U.S. cohort and the combined cohort, similar patterns were observed, with increased circulating TMAO correlating with a significantly increased adjusted risk for fast-growing AAA (aORs, 2.71 and 2.30, respectively) and recommended surgical intervention (aORs, 2.73 and 2.41, respectively). Significant improvement in both risk estimation for fast-growing AAA and predicting recommended surgical intervention was seen with the addition of TMAO to base models containing traditional cardiovascular risk factors.

“These results suggest targeting TMAO levels may help prevent and treat aneurysmal disease beyond surgery,” Cameron said in a statement. “With one of the largest volumes of aortic cases in the United States, we hope we can apply these findings to help future patients.”

Several authors disclosed ties to the biopharmaceutical industry; one author has a patent for trimethylamine-containing compounds for diagnosis and prediction of disease.

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