High LDL and total cholesterol are generally related to either conditions passed on in families (inherited conditions like familial hypercholesterolemia, or FH) or poor lifestyle. Unhealthy habits include:
Eating unhealthy fats and simple carbohydrates
Not exercising regularly
Being overweight or obese
In addition, you have a greater chance of heart disease or certain types of strokes if you have:
High blood pressure
Diabetes
Family history of early heart disease
Smoking or vaping
Low HDL cholesterol levels (also called the "good" cholesterol)
Certain autoimmune or inflammatory conditions, such as rheumatoid arthritis, lupus, psoriasis, among others