Many people struggle with high cholesterol. Before you identify what may be causing your high cholesterol levels, it's important to understand what cholesterol is. There are two main types of cholesterol. LDL, or, "bad" cholesterol is a substance that tends to clog and harden your arteries. HDL, or, "good" cholesterol carries LDL away from the arteries and into your liver to be eliminated. Here are seven factors that may be responsible for your high cholesterol levels.