Could be also something like https://en.wikipedia.org/wiki/Familial_hypercholesterolemia where it's just due to genes and bad luck. You can do generic tests for it, but they're relatively expensive. Statins mostly help bring the numbers down.
Emphasis on mostly. Check my post above. It's genetic for me most probably (I'm the 4th generation w/ high cholesterol and we cover most of the combinations of vegan/carnivore/fat/thin). Statins have bad side effects that can kill you outright. To think I'd been on statins since 16 years old (for round about 25 years... )
In this case I meant mostly as in "out of things they do, the big effect is on the cholesterol numbers". We still don't really know if they help with heart diseases or not. As far as I understand it, that still relies on the unproven hypothesis that lowering cholesterol numbers does improve the outcomes.