Doctors can determine a lifetime risk or a 10-year outlook for heart attack and stroke by a person's high-density lipoprotein levels and total cholesterol score, according to the American Heart Association. An optimal cholesterol score is less than 180 milligrams per deciliter.
Total cholesterol is determined by adding HDL, which is considered to be the "good cholesterol," and LDL, or "bad cholesterol," plus 20 percent of a patient's triglyceride level, states the American Heart Association. Higher levels of HDL are healthier, and lower levels may be an indication that triglycerides, a type of body fat, are high. Causes of low HDL include type 2 diabetes, obesity, smoking, genetic factors and the use of drugs such as steroids and beta-blockers.
As of 2015, LDL is less of a factor in predicting risk or determining prevention treatment, states the American Heart Association. Patients taking prescription medications no longer need to target specific LDL levels, but should reduce or eliminate saturated fats and trans fats in their diets in order to improve overall LDL. If triglyceride levels are high and either HDL is low or LDL is high, it may be an indication of atherosclerosis, a condition wherein the arteries are blocked by the buildup of fatty deposits. Atherosclerosis increases the risk of heart attack and stroke.