A high blood cholesterol level increases your risk of coronary artery disease. Lower cholesterol most often is better.

But rarely, having a very low level of low-density lipoprotein (LDL) cholesterol, also called the "bad" cholesterol, has been linked to some health problems. The same may be true for a very low total cholesterol level.

Researchers still are trying to find out more about the link between low cholesterol and health risks. They don't agree on how to define very low LDL cholesterol. But LDL cholesterol is very low if it's less than 40 milligrams per deciliter of blood.

It's not clear if low cholesterol causes certain health problems or if the health problems cause low cholesterol. For instance, people with depression may have low cholesterol levels. But studies haven't shown that lowering cholesterol with medicines called statins causes depression.

Some conditions, such as certain cancers, may cause low levels of LDL cholesterol. Low levels of LDL cholesterol may be linked to:

• Diabetes.
• Hemorrhagic stroke.

But research hasn't proved that there are risks of lowering LDL cholesterol to very low levels. And researchers still debate very low LDL cholesterol's link to certain health risks.

Recent trials using new treatments to lower cholesterol have helped people reach very low cholesterol levels with no increased risk of major side effects. But the follow-up has been short. So experts don't know the long-term effects of having very low cholesterol.

One long-term study found a link between very low LDL cholesterol and a higher risk of hemorrhagic stroke. More long-term data is needed to know about safety.

Many studies have shown that having lower than average total and LDL cholesterol is healthy. This is especially true in people with heart disease or at high risk of heart disease or stroke.

If you're worried about your cholesterol level, talk with your healthcare team. If you're taking statins, don't stop without first talking with your healthcare team. Your team can tell you what range your cholesterol level should be in.