Heart disease is the number one killer of men AND women in Western countries. It’s also very much a lifestyle disease. Research shows as many as 80% of heart-related deaths could be prevented by making healthy lifestyle choices. One area of focus has been lowering cholesterol via dietary changes but mainly with the help of popular cholesterol-lowering drugs called statins. Yet, 50% of all heart attacks occur in people with a low or normal cholesterol level. This would suggest that factors other than cholesterol are fueling heart disease. If that’s the case, lowering your cholesterol may not be the answer to preventing a future heart attack. In fact, other numbers tell us just as much or even more about the risk of dying of a heart attack than a cholesterol level. What are these numbers and what do they mean?
You hear a lot about total cholesterol and LDL-cholesterol but less about the cholesterol ratio. Cholesterol ratio is the ratio of total cholesterol over HDL-cholesterol, both measurable with a blood test. You get this value by dividing total cholesterol by your HDL. Some labs do this calculation for you and list the value on your lab report. The lab also lists a reference range that shows where your value falls on the risk scale.
Why is this ratio important? According to a study published in the Journal of the American Medical Association, cholesterol ratio is a better determinant of heart attack risk than total cholesterol or LDL-cholesterol values. In fact, based on this study, LDL and total cholesterol, as isolated values, aren’t strong predictors of heart attack risk. A lower cholesterol ratio is more favorable, corresponding to a high HDL-cholesterol relative to total cholesterol. An optimal value is less than 3.5. One lifestyle factor that can improve your ratio is aerobic exercise, since it raises HDL.
Triglyceride to HDL Ratio
Another value measured by a standard lipid profile are blood triglycerides. High levels of these circulating fats are a marker for insulin resistance. People with elevated triglycerides often have metabolic syndrome, a syndrome characterized by insulin resistance. Metabolic syndrome increases the risk of diabetes and heart disease. Men and women with metabolic syndrome typically have a high triglyceride level and a low HDL-cholesterol value or a high triglyceride to HDL ratio. A number of studies show that this ratio correlates strongly with the risk of heart attack and stroke. A triglyceride to HDL ratio above four places you in a high-risk category.
Your triglyceride to HDL ratio gives you a better idea of what size and shape the cholesterol particles you have are. Studies show that large, fluffy LDL-cholesterol particles are the least dangerous, while small, dense LDL-cholesterol particles are the most deadly. The small, dense particles have the easiest time invading the walls of arteries and causing blood vessel wall inflammation, a strong risk factor for heart attack and stroke.
Since most laboratories don’t measure particle size routinely, triglyceride to HDL is a marker for whether you have more dense or large, fluffy particles or small, dense ones. If you have a triglyceride to HDL ratio greater than 4, you probably have a higher ratio of small, dense LDL-cholesterol particles relative to big and fluffy, meaning your risk for heart attack or stroke is higher. For the lowest risk, your triglyceride to HDL ratio should be less than two.
High blood pressure damages the inner walls of arteries, the blood vessels that carry blood from your heart to the rest of your body. When arterial walls are damaged, they become inflamed and prone towards forming a dangerous blood clot. If that clot ruptures, you may have a heart attack or stroke. Plus, high blood pressure forces your heart to work harder to pump blood. Over time, this places significant strain on your heart. This strain can lead to structural changes that make your heart a less efficient pump. People who have long-term hypertension sometimes develop heart failure due to the inability of their heart to adequately pump blood and oxygen. High blood pressure can damage almost every organ in your body, including the kidneys and brain.
How common is high blood pressure? About one in three people in the U.S. has hypertension or pre-hypertension, meaning their blood pressure is consistently higher than 120/80. So, know your numbers by checking your blood pressure regularly. If it’s even borderline high, make lifestyle changes or, if necessary, medications to bring it down. Don’t forget, hypertension is often a silent disease, so you can’t count on symptoms to reveal it. Despite its silence, it can do significant damage to your heart, blood vessels, and organs, like your kidneys.
You might wonder what your blood sugar has to do with heart attack risk. More than you might think! A blood sugar that’s higher than normal but not yet in the diabetic range is a marker of insulin resistance, a strong risk factor for cardiovascular disease. A slightly elevated blood sugar can be a sign of metabolic syndrome, a risk factor for heart disease, whereas a significantly elevated one may be diabetes. Elevated blood sugar increases the risk of having a heart attack or stroke. In fact, diabetics are at 2 to 4 times greater risk of having a heart attack or stroke. The take-home message? Check your blood sugar regularly, keep your weight down, and stay active.
Your waist size also says something about your risk of developing cardiovascular disease. If you’re female and your waistline measures 35 inches or greater, you fall into a higher risk category for heart disease. The same goes for guys with a waist measurement of 40 inches or above. One study found that waist size is a strong predictor of poor functioning of the left lower chamber of the heart, called the ventricle, that pumps blood to the body. In fact, it’s a better predictor of heart disease risk than BMI or body weight. In addition, having a thick waistline is linked with other risk factors for heart disease, including elevated blood sugar, high blood pressure, and cholesterol issues. So, don’t just keep an eye on your cholesterol, watch your waistline too.
The Bottom Line
Total cholesterol and LDL-cholesterol are only two factors that impact your risk of cardiovascular disease. Experts are now debating whether cholesterol causes heart disease at all, especially when half of the people who have heart attacks have a normal LDL-cholesterol value. Don’t assume that because you have a normal cholesterol that your risk of heart attack or stroke is low. Make sure you know these other numbers and discuss them with your doctor.
JAMA 298(7): 776-85. 2007 Aug 15.
International Journal of Hypertension. Volume 2011 (2011), Article ID 281240, 8 pages.
GMA News Online. “Waist size ‘strongly predicts’ heart disease risk: study”
World Heart Federation. “Diabetes”