I think they may already be onto the root cause, and it’s surprising. According to a study published in 2013 (https://pubmed.ncbi.nlm.nih.gov/23563705/) and some related heart studies as recently as last year, L-carnitine digestion by the gut microbiome effectively fosters certain gut bacteria that release chemicals in the blood that create conditions for artheriosclerosis.

i.e., it might be our gut mocrobiome at work in a negative way, where genes play a role in how our bodies and microbiome react more than others to create these negative conditions.