Heart disease is the leading cause of death in the United States. In 2010, according to data from the Centers for Disease Control and Prevention, 597,689 people in the U.S. died as a direct result of heart disease, a broad and encompassing term that includes diseases of your blood vessels, heart arrhythmias, heart infections, and congenital heart defects. By comparison, the fourth through 10th most common causes of death combined (including stroke, diabetes, Alzheimer's disease, accidents, and influenza/pneumonia) don't even add up to the number of deaths claimed by heart disease on an annual basis.


Source: Centers for Disease Control and Prevention.

As you might suspect, being the leading cause of death in the U.S., untold amounts of money and research has gone into ways to improve patient's quality of life and to understand what risk factors exist that trigger one or multiple facets of this disease.

Keeping that in mind, I propose to look at the 10 most common risk factors that contribute to heart disease as outlined by the Mayo Clinic and the National Institutes of Health. "Why?" you ask? For two reasons. One, knowledge is power. The more you understand what the risk factors are, and whether you are a higher-risk candidate in the first place, the more you can do to reduce your chances of developing heart disease. Secondly, in addition to taking care of your personal health, the well-being of your financial health is also important. At The Motley Fool we're always looking for ways of identifying companies that are making a difference in the health-care industry with their treatment options, and there are few instances with more opportunity than in treating and/or preventing heart disease symptoms.

Without further ado, here are the 10 most common risk factors for heart disease (in no particular order):

1. Hypertension
You may know hypertension by its less-scientific name, high blood pressure. The downside of having consistently high blood pressure is that it tends to thicken and harden arteries over time and can shrink blood vessels, making it harder for your heart to pump blood throughout your body. A study released by the CDC in September 2012 highlighted the dangers of this symptom in its Morbidity and Mortality Weekly Report. In that report, the CDC notes that 66.9 million American adults (30% of the population) suffers from high blood pressure, of which more than half (53.5%) do not have their hypertension under control and another 39.4% of Americans with hypertension are unaware they even have high blood pressure!

What unique therapy might be called upon to help stave off a rise in hypertension? There are more than a handful of choices, and it could take some time before physicians find out what type of therapy (i.e., ACE inhibitors, beta blockers, calcium-channel blockers, renin inhibitors, and so on) works best from person to person. One drug that I have my eye on for continued growth is Forest Laboratories' beta blocker, Bystolic. It works by blocking specific nerve and hormonal signals to the heart and blood vessels, causing blood vessels to relax and blood to flow more easily. Sales of the drug grew by 17% year-over-year in the first quarter and should be able to grow by double digits for the foreseeable future.

2. High blood cholesterol
Although two separate risk factors, you'll often see high cholesterol and hypertension go hand-in-hand. Specifically, low-density lipoproteins, or LDL-cholesterol, is the one people need to watch out for. This "bad" cholesterol can lead to the formation of plaques or atherosclerosis in blood vessels, hardening them over time and making it difficult for the heart to pump blood throughout the body. As equally scary as the hypertension statistics, the CDC notes that 71 million persons have high LDL-cholesterol levels, and slightly more than half aren't doing anything to adequately bring their LDL-cholesterol under control.

I know I've beaten a dead horse with this drug lately, but Liptruzet, the LDL-reducing drug that combines Pfizer's (PFE 2.40%) now generic statin Lipitor with Merck's (MRK 0.44%) cholesterol absorption inhibitor Zetia, could be a monster treatment moving forward. Separately, Zetia and Lipitor reduced LDL cholesterol levels by 20% and 37%-54% in clinical studies. Liptruzet, though, further boosted that range to an LDL-reduction of 53%-61% while also boosting high-density lipoprotein production (the good type of cholesterol).

3. Your age
As you'll see, some of the risk factors on this list are easy to work with through a change in lifestyle habits. Your age, unfortunately, is not one of them. No matter how many times you want to celebrate that 29th birthday, you're always growing older, and the risk of developing a type of heart disease grows as you age. In fact, according to the Texas Heart Institute, approximately four in every five cardiovascular deaths occurs in someone over age 65. As we age, our blood vessels can damage more easily and the muscle around our heart can thicken, which makes it tougher for the heart to pump blood. Obviously, staying active and eating right will help stave off certain aspects of this risk factor, but ultimately, there's nothing we can do about getting older.

4. Your gender
This one is a bit tricky, because it tends to even out as we age, but generally speaking, men are prone to getting heart disease than women. According to the National Institutes of Health, this is because estrogen provides women with some level of heart disease symptom prevention before menopause. However, once menopause occurs in women and estrogen production dips, the probability of developing one or more of the risk factors associated with heart disease shoots way up for women. By age 65, the chance of developing one or more of the risk factors associated with heart disease is equal between men and women.

5. Diabetes
As you've probably noticed by now, diabetes is a common risk factor for a number of serious diseases, including heart disease. Characterized by a struggle to maintain proper glycemic balance, diabetes comes in two forms: type 1 diabetes (those genetically predisposed to the disease) and the considerably more common type 2 diabetes (those who develop diabetes because of a mix of improper diet, exercise, and perhaps other genetic factors). The primary concern for diabetics and pre-diabetics as it relates to developing heart disease is that high blood sugar can lead to the development of plaque in the arteries over time, making it difficult for blood to flow throughout your body.

The intriguing news, though, for the 25.3 million people who have diabetes and 79 million who are pre-diabetic, is that a new class of diabetes treatment has made its way to U.S. markets that could revolutionize type 2 diabetes care. The drug, Invokana, which is made by Johnson & Johnson (JNJ 1.49%), is a new class of diabetes drug known as an SGLT-2 inhibitor. Rather than working in the pancreas or liver, as its preceding diabetes medications have done for more than a decade, Invokana works in the kidneys to block glucose absorption and allow the patient expel excess glucose in their urine. Furthermore, Invokana was shown to have the added benefit of lowering systolic blood pressure and inducing weight loss in patients.

6. Obesity
Like diabetes, being overweight or obese goes hand-in-hand with increase your risk of developing a number of diseases, including heart disease. As I highlighted in June, cardiovascular diseases (i.e., heart disease) is the second-most common disease directly caused by obesity. While carrying around extra weight does add to the burden of your heart to pump blood throughout your body, it's the exacerbating circumstances that are the bigger worry here. Diabetes is the No. 1 disease caused by obesity, and, as we just saw, it's one of the primary risk factors for developing heart disease. Obesity is also a contributing factor to higher cholesterol and blood pressure levels in many instances.

Although they've yet to really see sales get off the ground, chronic weight-management drugmakers such as Arena Pharmaceuticals (ARNA) with Belviq and VIVUS (VVUS) with Qsymia have an opportunity to shine. As I've stated previously, Qsymia presented the better overall weight-loss percentage in clinical trials, but Belviq had the more favorable safety profile, so it's really anyone's guess which drug will lead the pack. Ultimately, it may not matter, as the obesity epidemic should easily accommodate both drugs and perhaps even more competitors down the road. 

7. Lack of proper diet
In case you haven't heard it 100 times before, what you eat does matter! Obviously, genetic traits predispose some people to certain risk factors of heart disease no matter how healthfully they eat. But for the remainder of us, foods that are high in saturated fat, salt, or cholesterol can, over time, raise our cholesterol level or blood pressure, and/or induce plaque to build up in our arteries. Alcohol represents another risk factor that has the potential to add weight and increase blood pressure if used on a regular basis. The obvious solution here is to eat as balanced a diet, complete with fruits and vegetables, as is possible, and if you choose to drink, to do it in moderation.

8. Family history
As I just noted, some people are genetically predisposed to a higher chance of developing the risk factors associated with heart disease. The National Institutes of Health points out that your risk factor of developing heart disease jumps if you have a father or brother who developed heart disease before age 55, or a mother or sister with heart disease before age 65. However, to clarify, the NIH also makes sure to note that your chance of developing heart disease is also predicated on lifestyle choices exhibited by those individuals which may have included smoking, an inactive lifestyle, drinking alcohol, or other factors that weren't well cared for.

Source: Jo Naylor, Flickr.

9. Lifestyle choices
Speaking of lifestyle choices, people who choose to smoke and drink alcohol put themselves at a significantly higher risk of developing heart disease than those who don't. Specifically, nicotine, which is found in cigarettes, is a vasoconstrictor (blood vessel constrictor), and the carbon monoxide found in cigarettes can, over time, damage the inner lining of blood vessels, giving smokers a higher chance of having a heart attack than non-smokers.

A sedentary lifestyle is also a mitigating risk factor. Those who live a non-active lifestyle are more prone to weight gain and developing plaque buildup and atherosclerosis in their blood vessels.

10. Poor hygiene
Finally, failing to regularly wash your hands, brush your teeth, and do all of those unpleasant tasks your parents beseeched you to do as a kid could leave you at a higher risk of developing a heart infection, especially if you have a genetic heart condition or have already had a heart attack.

Now that you have a better understanding of the mitigating risk factors for heart disease, hopefully you can make the lifestyle changes necessary to reduce your risk of developing this disease. Along the way we also reviewed some potential investing ideas that could ultimately reduce your financial stress and improve your overall heart health. Overall, I'd call that a win-win kind of day!