Fats (lipids) in the blood are one of the main factors other than smoking and high blood pressure causing arterial disease. Cholesterol, HDL and LDL are the most important fats involved in arterial disease, of these LDL is the most important.
It is important not just to have the total cholesterol measured but your “lipids” – this will give the breakdown of the cholesterol as well as HDL and LDL fractions of the total cholesterol.
A bad diet can cause a high LDL but genetics are often a significant factor and can cause extremely high levels.
There is now excellent treatment for all the blood lipids if needed.