Research in the last few years suggests the commonly upheld notion that high levels of LDL (or bad cholesterol) and low levels of HDL (or good cholesterol) lead to heart attacks may not be true, after all. Most recently a 2011 study published in the The Journal of Clinical Endocrinology and Metabolism found that low levels of HDL, while associated with heart attacks, aren’t the cause. Another 2011 study, published in The Lancet, found that among people with normal levels of LDL levels, the presence of calcium in coronary arteries was a more significant predictor for heart attack and stroke. And previous research has shown that almost half of patients hospitalized for heart disease have LDL levels lower than 100 — a level considered “optimal” by the National Heart Lung and Blood Institute.
So why do people with normal cholesterol numbers have heart attacks? And why do some people with high cholesterol escape heart disease? Ultimately, plaque build-up in the arteries is what causes heart attacks. And while high LDL cholesterol is a contributing factor to plaque build-up, LDL levels simply show the percentage of bad cholesterol in the blood. Recent studies show that heart attack risk may actually have more to do with the size of cholesterol particles and their total number rather than the total amount of LDL cholesterol in the blood. (Oddly enough, smaller LDL particles seem to pose a greater risk of heart attack, according to a recent report from the Mayo Clinic.)
Because a standard blood test for cholesterol doesn't reveal information about LDL particle size, you need a separate test, which isn't widely available, according to the Mayo Clinic report.
Still, as Danya L. Dinwoodey, MD, a cardiologist at the Lahey Clinic in Burlington, Mass., explains, "high cholesterol levels are only about 50 percent of your heart attack risk. There is no single risk factor that can predict who will have a heart attack.”
And, she adds, "Some treatable diseases like diabetes, peripheral vascular disease, and chronic kidney disease put you at higher risk than high cholesterol."
The more heart disease risk factors you have, Dr. Dinwoodey says, the higher your overall heart attack risk. In addition to keeping your cholesterol levels in check, here are some other risk factors to note and change if you can.
Heart Attack Risk Factors You Can't Change
"Even if you do everything right, there are some heart attack risks you can't avoid," Dinwoodey says. These are:
- Family history. If one of your parents had or has heart disease, you have at least one risk factor for heart disease. If you are African-American, Mexican-American, or Asian-American, your risk for heart disease — and therefore heart attack — is also higher.
- Age. Once you are 65, your risk for heart attack increases.
- Sex. If you are a man, you have a higher risk for heart attack at any age, but women are not immune. "Heart disease [risk] for women does increase with age," says Dinwoodey.
Major Heart Attack Risk Factors You Can Change or Treat
These are called modifiable risk factors because you may be able to do something about them. High cholesterol is high on the list of modifiable risk factors, as are these:
- Smoking. According to the U.S. Centers for Disease Control and Prevention (CDC), 20.8 percent of Americans still smoke. If you smoke a pack of cigarettes per day, your risk of having a heart attack more than doubles over that of someone who doesn’t smoke.
- High blood pressure. High blood pressure increases your risk for heart attack and also increases your risk of stroke and kidney failure.
- Physical inactivity. Not exercising regularly contributes to risk for heart attack, obesity, high cholesterol, diabetes, and high blood pressure.
- Obesity. Like inactivity, obesity increases most of your other risk factors. The worst type of weight for heart disease is belly fat — losing just 10 pounds can greatly reduce your risk.
- Diabetes. At least 65 percent of people with diabetes die of some type of heart disease or blood vessel disease. To best prevent developing heart disease on top of diabetes, manage your condition well, with help from your doctor, eat a healthy diet and exercise to maintain a healthy weight.
Contributing Risk Factors You Can Also Control
Your work is not yet done. In addition to those major risk factors, there are some contributing factors you need to pay attention to:
- Stress. Emotional stress can put stress on your heart and may contribute to a tendency to overeat and smoke. Identify your stressors and adopt techniques to control stress.
- Diet. You can positively affect risk factors like high cholesterol, obesity, high blood pressure, and diabetes with a diet that is high in fruits, vegetables, whole grains, lean proteins, and low-fat dairy.
- Alcohol. A little alcohol may be good for your heart, but only a little. Too much alcohol contributes to high blood pressure and other risk factors. Sip no more than two drinks a day if you’re a man and one drink a day if you’re a woman.
Even though cholesterol may not be as potent a heart disease risk factor as once believed, it's still important to keep your levels healthy as part of your overall heart-health plan. Everyday Health expert Arthur Agatston, MD, a preventive cardiologist and an associate professor of medicine at the University of Miami Miller School of Medicine, says your doctor should evaluate your total cholesterol along with other cardiac risk factors, including family history of heart attacks or strokes. "If you are at risk for a heart attack," he says. "Then lowering your cholesterol, no matter what level it was at the start, can be life saving."