It mainly depends on your family's health history. If your parents and or grandparents had it, then there's a high chance that you'll get it also.
My mom and one of my brothers had it, my oldest brother and I have it. It ran like wildfire on my father's side of the family. And it's mostly known that obesity is one of the main causes, as is high blood pressure, stress, high cholesterol levels and other things. If it's in your family genes, yes, you're a prime candidate for it.
But skinny people can get it as well, so it does not discriminate.
My dear brother who died as a result of not doing the right thing to at least control it, left behind a loving caring wife and two sons. I told his two sons that they must keep and eye out for any symtoms of diabetes, because they are now at risk for getting it since their dad had it.
I haven't heard anything about DNA causing it. But it's most likely that Afro-Americans, Spanish, Asian, Italians, White and other nationalities have it running in their families as we speak. Because more than likely, diabetes ran in their families even before THEY were born.
Oatmeal IS one of the best defenses against bad cholesterol, along with any medicine you might be on for it. But you should still see your doctor so that he or she can help monitor it in your blood, letting you know if it went down.
The norm now is to take your medicine, eat healthy, exercise and see your doctor. And eat oatmeal for breakfast for at least a month to see if you've lost any of the bad cholesterol.