High cholesterol is one of the biggest risk factors for heart attack, stroke and cardiovascular disease, according to the Cleveland Clinic. Your cholesterol ratio, which compares your total cholesterol to your HDL, or "good," cholesterol, can help better assess your risk.
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While a healthy total cholesterol is less than 200 milligrams per deciliter (mg/dL), the ideal ratio of total cholesterol to HDL is a bit more complicated. Here's what you need to know.
Read more: What Is a Dangerous Cholesterol Level?
Good Cholesterol vs. Bad Cholesterol
In order to understand cholesterol ratios, it's good to know a bit more about the different types of cholesterol.
Cholesterol is a waxy, fat-like substance that is crucial for the body to function properly, according to the Harvard T. H. Chan School of Public Health. You may think that all cholesterol is "bad." But the truth is that only some kinds of cholesterol are a health concern, and then only in high quantities.
Low-density lipoproteins (LDL) are the so-called "bad" kind of cholesterol, according to the American Heart Association (AHA). If there is too much LDL in the bloodstream, it can combine with other substances like calcium and form deposits on the artery walls. These deposits — called plaque — narrow and stiffen the arteries, a condition called atherosclerosis. Atherosclerosis significantly increases the risk of heart attack, stroke and cardiovascular disease.
High-density lipoproteins (HDL) are the "good" kind of cholesterol, per the AHA. HDL moves through the bloodstream and picks up excess LDL particles before returning them to the liver for disposal. In this way, HDL helps prevent plaque buildup and heart disease.
Is My Cholesterol Ratio Healthy?
There are several types of cholesterol tests, sometimes called a lipid panel. One test measures a person's total cholesterol level. A healthy total cholesterol is less than 200 mg/dL, according to the U.S. National Library of Medicine. But if a person has high HDL cholesterol (the good kind), it can cause elevated cholesterol overall. This is why measuring different types of cholesterol is so important.
A ratio is simply a comparison between two numbers. A cholesterol ratio compares a person's HDL cholesterol to the total cholesterol in the body, according to the Mayo Clinic.
How to Calculate Cholesterol Ratio
This number is found by dividing the total amount of cholesterol by the HDL number. For example, if a person has an overall cholesterol level of 225 mg/dL and an HDL of 80 mg/dL, his or her cholesterol ratio is 2.8-to-1, also written as 2.8:1 or simplified to cholesterol ratio 2.8.
A healthy cholesterol level is no more than 5:1, according to the University of Rochester Medical Center. But the lower the ratio, the better. A ratio of 3.5:1 or lower is considered very good.
However, Robert Eckel, MD, professor of medicine, emeritus, at the University of Colorado, Anschutz Medical Campus, former president of the American Heart Association and president of the American Diabetes Association, doesn't think cholesterol ratios are the most accurate way to determine a person's risk for cardiovascular disease.
"Ratios are misleading. The result is related to HDL, but a person's LDL level remains important," Dr. Eckel says. Essentially, if a person has both high HDL and LDL, the ratio between the two can still be normal, even if their LDL cholesterol is in an unhealthy range. Instead, Dr. Eckel prefers measuring non-HDL cholesterol.
Per the Mayo Clinic, many doctors now use non-HDL tests to assess a person's risk. A non-HDL measurement is exactly what it sounds like — a measurement of all the cholesterol in the body, minus the HDL. A healthy, non-HDL cholesterol level is less than 130 mg/dL.
High cholesterol doesn't usually cause symptoms, according to the American Academy of Family Physicians. Be sure to have your cholesterol level checked regularly, per your doctor's instructions.
High Cholesterol Risk Factors
High cholesterol is often caused by poor lifestyle habits, according to the AHA. An unhealthy diet (particularly one high in saturated fats), along with a lack of exercise and being overweight can lead to high cholesterol. Smoking cigarettes is also a major risk factor for raising LDL cholesterol.
But there is good news. Because many high cholesterol risk factors are lifestyle related, lifestyle changes can reduce your risk, per the AHA. Healthy diet choices, exercising regularly, reaching and maintaining a healthy weight and quitting smoking are some of the best things you can do to lower your cholesterol — and improve your overall health.
There are also non-lifestyle-related high cholesterol risk factors, per the AHA. These include genetics (inherited traits), older age and sex — men are more at risk for high cholesterol than women.
If you're concerned about your cholesterol, talk to your doctor about lifestyle changes or medications that might help get your numbers into a healthy range.
- Cleveland Clinic: "Cholesterol Guidelines & Heart Health"
- Harvard T. H. Chan School of Public Health: "Cholesterol"
- American Heart Association: "HDL (Good), LDL (Bad) Cholesterol and Triglycerides"
- U.S. National Library of Medicine: "Cholesterol Levels"
- Mayo Clinic: "Cholesterol Ratio or Non-HDL Cholesterol: Which is Most Important?"
- University of Rochester Medical Center: "Lipid Panel With Total Cholesterol: HDL Ratio"
- American Academy of Family Physicians: "High Cholesterol"
- American Heart Association: "Causes of High Cholesterol"
Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.