Dear Doctors: I read that, when you take statins, it raises blood glucose levels to a prediabetes or diabetes level. My blood glucose is a bit high, and I’m worried it will go out of the normal range if I take them.

Answer: Statins are a class of drug that can help lower unhealthful cholesterol levels in the blood. This can lower the risk of developing certain types of heart disease. 

Cholesterol — a fatty, waxlike substance — is found throughout the body. It plays a key role in functions including maintaining flexibility of cell membranes and aiding in synthesis of hormones and vitamins. 

The liver produces the cholesterol we need. But diet, smoking, poor blood sugar control, being overweight or sedentary can cause cholesterol levels to rise. Excess levels can lead to formation of thick, hard deposits called plaques along the walls of the arteries. This can lead to blockages and atherosclerosis, which increases the risk of heart attack and stroke. Plaque also can build up in arteries that serve the heart. That’s known as coronary artery disease.

When someone takes statins, it reduces the amount of low-density lipoprotein — LDL, the “bad” cholesterol — the liver produces. LDL binds with other substances to form plaques. Statins block a liver enzyme involved in cholesterol formation, can help remove LDL from the blood and play a role in stabilizing existing plaques. 

Statins’ potential side effects include muscle pain, headache, brain fog and fatigue.

Recent research also has linked statins to an increased risk of developing insulin resistance, in some cases leading to pre-diabetes or Type 2 diabetes. Why isn’t fully understood. 

Statins don’t cause elevated blood sugar levels in everyone who takes them. An analysis of studies found this occurs in about 9% of people using the drugs. Developing insulin resistance has been associated with moderate to high doses of the drug and happens more in people whose blood sugar levels already were high.

Discuss your concerns with your doctor. If your medical profile and history put you at risk of developing insulin resistance while on the drug, your doctor can help you take steps to protect yourself. These include dietary and lifestyle changes, regular screenings for changes to blood sugar control and possibly an alternative drug therapy for managing cholesterol.

Dr. Eve Glazier and Dr. Elizabeth Ko are internists at UCLA Health.