I have a theory that rather than heart disease being genetic, it is environmental that is passed down through family. Lets say your family eats a certain way w

I have a theory that rather than heart disease being genetic, it is environmental that is passed down through family. Lets say your family eats a certain way when you are young, and your family members die of heart disease. And you continue that pattern into adulthood, eating the same way you were brought up, and you get heart disease. Is it genetic or is it passed-down environmental? I think it's the latter.