Dietary Choline and Betaine Intakes and Risk of Cardiovascular Diseases: Review of Epidemiological Evidence
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3347848/

Usual choline and betaine dietary intake and incident coronary heart disease: the Atherosclerosis Risk in Communities (ARIC) study.
https://www.ncbi.nlm.nih.gov/m/pubmed/17629908/