What Causes Heart Disease?

Many people understand that there is a connection between poor diet, lack of exercise and the development of heart disease. But your risk of developing cardiovascular disease is the result of a combination of many risk factors. There are two main categories of risks that contribute to heart disease—those that you can't change (uncontrollable risks), and those that you can (controllable risks).

Uncontrollable Risk Factors
These variables are out of your control. Although you can't do anything to change them, it's important to know whether you fall into any of these higher-risk categories. How many of these risk factors do you exhibit?
  • Your age. Men over 45 and women over 55 are more likely to develop heart disease than their younger counterparts. The American Heart Association (AHA) states that more than 83 percent of people who die of coronary heart disease are 65 or older. Why? Plaque begins to slowly deposit in the arteries starting in childhood, so simply getting older increases your risk of developing heart disease and having a heart attack. The older you get, the more likely you are to have damaged arteries and/or a weakened heart muscle. Most people have plaque buildup in the arteries by the time they reach their 70s, according to the National Heart Lung and Blood Institute, but only about one-quarter of these people will exhibit signs or symptoms of cardiovascular disease.
     
  • Your sex. Overall, more men have heart attacks than women do, and they experience them earlier in life, too. While a woman's risk of dying from heart disease increases after menopause, it's still lower than a man's.
     
  • Your family history. If people in your family have heart disease—especially close or immediate relatives, your risk of developing it increases. If a parent or sibling developed heart disease at an early age (before age 55 for men, or before age 65 for women), your risk is even higher. Developing heart disease isn't necessarily in your DNA, however. Lifestyle habits (diet, exercise, smoking, drinking, etc.) tend to be passed down from generation to generation, which means that some portion of this risk is controllable.
     
  • Your race. Somewhat related to family history, your race can also predetermine part of your risk of heart disease. African Americans, American Indians, Mexican Americans, and native Hawaiians are more likely to have heart disease than Caucasians, but this is partly due to other risk factors that these populations tend to experience, such as diabetes and high blood pressure.
     
  • Your body type. Whether or not you become overweight or obese is mostly within your control, but you cannot control your weight distribution, which refers to where your body stores fat. For years, experts warned that people who tend to carry excess weight in their belly area (known as "apple" shapes) are at a greater risk of several health problems, including heart disease, while "pear" shaped bodies that store more fat in the lower body don't have the same risk. However, one 2010 study published in The Lancet dispelled that idea, saying that being overweight (regardless of where your body stores the fat) is a heart disease risk factor. Your genetics determine your body type; if you are apple-shaped now, you will always be apple-shaped, even if you lose weight. Still, maintaining a healthy body weight—which would decrease your waist circumference—is a controllable risk factor (more on that below) that can reduce your heart disease risk.
Controllable Risk Factors
Factors that you can control are related to your lifestyle—the choices you make each day about what to eat and whether or not to exercise. These are areas of your life where you can take control to reduce your risk of heart disease and enhance your overall health.
  • Smoking. Most people think of lung cancer when they think of smoking, but did you know that smoking is the leading preventable cause of heart disease and heart attack? People who smoke are 2-4 times more likely to develop heart disease than non-smokers, according to the AHA. Smoking damages the walls of your arteries, constricts blood vessels, and lowers your HDL (good) cholesterol levels. Quitting smoking can stop (and potentially reverse) a lot of the existing damage to your body. The American Lung Association says that after one year of quitting, an ex-smoker's heart disease risk is half that of a smoker's, and after 15 years without lighting up, it's as low as a nonsmoker's. Don't smoke? Good! But stay away from tobacco smoke anyway. Exposure to secondhand smoke increases the risk of heart disease even for nonsmokers.
     
  • Your diet. A diet that's high in saturated fat, trans fat, sodium, added sugars, cholesterol can raise your cholesterol and blood pressure levels and increase your risk of heart disease. Some research shows that diets too high in animal-based foods (meat and high-fat dairy products) and too low in plant-based foods like whole grains, fruits, vegetables and nuts can lead to heart disease, too. Learn more about the foods that help fight heart disease.
     
  • Your activity level. If you're inactive, you're almost twice as likely to develop heart disease as people who get moving on a regular basis, reports the National Heart, Lung and Blood Institute (NHLBI). Regular exercise naturally decreases the LDL (bad) cholesterol levels in your blood while increasing your HDL (good) cholesterol levels. It also lowers blood pressure and helps with blood sugar control, not to mention that exercise strengthens the heart and cardiovascular system so that it is more efficient. Exercise does not have to be strenuous to offer benefits. Get a heart-smart workout plan here.
     
  • Your weight. The more excess body fat you have, the greater your risk of heart disease and heart attack—even if you have no other risk factors. Being overweight increases your blood LDL (bad) cholesterol and triglyceride levels, lowers HDL (good) cholesterol, and exacerbates other heart disease risks like diabetes and high blood pressure. Plus, carrying excess weight simply puts additional strain on the heart, forcing it to work harder. Calculating your body mass index (BMI) is one way to determine if you are overweight; losing just 10% of your body weight (if you are overweight) can improve your heart health.
     
  • Stress. Experts aren't sure why people with chronic stress have higher rates of heart disease, but they believe that stress (and the hormones it releases) may damage the arteries over time and make blood clots more likely to form. Just one stressful episode can elevate the heart rate and blood pressure for a short period, and even lead to a heart attack. Some people find unhealthy ways to deal with stress, such as overeating, smoking, or drinking (all risk factors in their own right). Identifying your stressors and dealing with them in a healthy way can help protect your heart.
     
  • Your drinking habits. Drinking too much—and possibly too little—seems to increase one's risk of heart disease. People who drink moderately (defined as an average of one drink day for women and two drinks daily for men) have a lower risk of heart disease than nondrinkers. However, the AHA does not recommend that teetotalers start drinking (or that drinkers increase the amount they drink) in order to achieve these purported benefits. Drinking too much has far more risks than not drinking. Too much alcohol can raise blood pressure and triglycerides, as well as contribute to obesity, irregular heartbeat, cardiomyopathy, alcoholism, heart failure, cancer, stroke and other diseases. To protect your heart, cut back on drinking; if you don't drink often—or at all—don't start.
Other Major Risk Factors
The following risk factors are largely controllable. Some people think of them as "symptoms" of heart disease, where others may view them as precursors.
  • High blood pressure (hypertension). Uncontrolled blood pressure can increase the workload of your heart, as well as harden and thicken the arteries, making it harder for blood to pass through. According to the AHA, high blood pressure coupled with other risk factors like obesity, smoking, high cholesterol or diabetes increases the risk of heart attack and stroke several times over. In many cases, high blood pressure can be controlled through lifestyle changes and medications.
     
  • High cholesterol. As cholesterol levels rise, so does your risk for cardiovascular disease. High cholesterol (especially high levels of LDL or "bad" cholesterol) can lead to artery blockage and damage, which contributes to heart disease and can lead to a heart attack. If you have high cholesterol along with other risk factors (like high blood pressure or tobacco use), you are at a much higher risk for heart disease. While some people are genetically predisposed to high cholesterol levels, lifestyle changes and medications can help control cholesterol levels.
     
  • Type 2 diabetes. People who have type 2 diabetes are twice as likely to experience heart disease or stroke—even if it is well managed. 65% of people with diabetes die of some form of cardiovascular disease, according to the AHA. If poorly managed, the risk is much higher, as uncontrolled blood sugar levels can damage the heart and veins. Type 2 diabetes is preventable. If you have diabetes, it's extremely important to work with your healthcare provider to manage your condition and reduce any other risk factors you may have.
Some of these risk factors put you at greater risk of heart disease than others. The more risk factors you have, the higher your chances of developing heart disease. The good thing is that you can break that chain of progressive disease at any point by working to reduce your controllable risk factors. You should work closely with your doctor to develop a heart-smart plan that is safe and effective for you. These plans usually involve some combination of dietary changes, exercise, medication and weight loss.

Sources
Mayo Clinic. "Heart Disease Risk Factors," accessed March 2011. www.MayoClinic.com

Centers of Disease Control and Prevention. "Heart Disease Risk Factors," accessed March 2011. www.cdc.gov.

Huffington Post. "Is the Apple or Pear-Shaped Body Type More Dangerous?," accessed March 2011. www.huffingtonpost.com.

National Heart, Lung and Blood Institute. "Coronary Heart Disease Risk Factors," accessed March 2011. www.nhlbi.nih.gov.

WebMD. "Risk Factors for Heart Disease," accessed March 2011. www.webmd.com.

Texas Heart Institute. "Heart Disease Risk Factors," accessed March 2011. www.texasheartinstitute.org.

American Heart Association. "Risk Factors for Coronary Heart Disease," accessed March 2011. www.heart.org.