The 3 Biggest Risk Factors for a Stroke

Often referred to as "the silent killer," stroke is the fourth-leading cause of death in the U.S., behind only heart disease, cancer, and chronic lower respiratory diseases. According to the Centers for Disease Control and Prevention, an estimated 795,000 people suffer a stroke each year, and nearly 130,000 died from their stroke in 2010.

Source: Centers for Disease Control and Prevention.

The danger inherent in strokes, which is rapid loss of brain function derived from a blockage of blood flow to the brain, is that many of the symptoms are often ignored or dismissed until it's too late. These symptoms can include headache, sudden loss of vision in one or both eyes, paralysis or numbness in your face, arms, or legs, trouble walking, and trouble speaking or comprehending speech. Worse yet, it takes but a few minutes, depending on the type and severity of the stroke, to cause permanent brain damage, making time of the essence when recognizing these symptoms.

As we've done in recent months by examining the risk factors and treatments associated with the most common types of cancer and diabetes, I propose to more closely examine the three biggest risk factors that can cause a stroke, discuss what treatment options exist, if any, to help mitigate that risk, and as always, discuss what investment potential these top treatments may have for your portfolio.

According to the CDC, there are three big factors that can lead to stroke:

  • Medical conditions.

  • Behavioral factors.

  • Hereditary factors.

Medical conditions
Listed by the CDC are six common medical conditions that have been shown to increase stroke risk. The good news is that, in most cases, treatments and lifestyle changes are available that will improve these conditions and thus lower your chance of having a stroke.

  • Hypertension: Also known as high blood pressure, hypertension can be brought on by a number of factors, including smoking, unhealthy eating habits, obesity, and even stress. In cases where stress mitigation, exercise, and healthier food aren't enough, a commonly prescribed treatment that might be called upon is Novartis' Diovan. Although Diovan is no longer under patent protection, no generic biosimilar has made it to market as of yet, leaving the door open for continued sale. Revenue totaled north of $900 million last year alone.

  • High cholesterol: High cholesterol can cause fatty deposits known as plaque to build up in your blood vessels, potentially leading to high blood pressure and/or a blockage, and thus increasing your chance of a stroke. Diet and exercise can mitigate some of these concerns, but high cholesterol can also be a hereditary condition that runs in the family. In those cases, and in cases of high cholesterol where lifestyle changes aren't enough, the most commonly prescribed drug in history, Pfizer's Lipitor, may be called upon. Before it went into generic form, Lipitor had an astounding $131 billion in lifetime sales.

  • Heart disease: With heart disease you have a wide range of potential complications, ranging from fatty deposits based on your diet and exercise habits that can clog blood vessels, to genetic factors like heart valve defects and enlarged heart chambers that can put you at an increased risk for stroke. For patients suffering from genetic types of heart disease, corrective surgery is often needed to correct the problem and allay stroke risks.

  • Diabetes: Diabetes comes in two forms: type 1 and type 2. Type 1 diabetes is purely based on genetic factors, while type 2, the considerably more common type, accounting for 90% of all cases, develops over one's lifetime and can be exacerbated by poor diet, lack of exercise, and smoking, to name a few factors. It's a risk factor for stroke because high blood sugar is often linked with high blood pressure and high cholesterol. Perhaps the most exciting new medication on the market, at least in the U.S., is Johnson & Johnson's SGLT2 inhibitor, Invokana. This new class of type 2 diabetes drug works in the kidneys by allowing people to get rid of excess glucose in their urine while also providing the added side effect of weight loss.

  • Being overweight or obese: Being overweight or obese carries with it a propensity for high blood pressure, high cholesterol levels, and an increased risk of getting type 2 diabetes. For many people, a lifestyle change involving diet and exercise can reduce their weight, but the recent approval of two chronic-weight-management pills, Belviq from Arena Pharmaceuticals and Qsymia from VIVUS , as adjuvant therapies could help even more. It remains to be seen which anti-obesity drug will come out on top, but VIVUS' Qsymia demonstrated the better weight-loss totals in trials relative to Belviq, while Belviq had the better safety profile compared with Qsymia.

  • Previous stroke or TIA: This might go without saying, but patients who have had a previous stroke or transient ischemic attack, or TIA, also known as a mini-stroke, are at more risk of having another stroke. People who have had a TIA are nine times as likely to have a stroke than people who've not had a TIA previously, according to Bay Area Medical Information.

Behavioral factors
The CDC refers to them as behaviors -- I refer to them as lifestyle choices. According to the CDC, there are three behaviors people exhibit that put them at greater risk of developing some of the aforementioned medical conditions.

  • Tobacco use: Cigarette smoking has been shown to be a damager of blood vessels and a dangerous risk factor for non-smokers via secondhand smoke. A study presented in 2011 at the Canadian Stroke Congress showed that smokers were more than twice as likely as non-smokers to have a stroke, and that on average smokers had their strokes a full decade before non-smokers. One way officials are looking to counteract this trend is by increasing awareness regarding the dangers of smoking. For instance, the CDC spent $54 million last year on graphic multimedia advertising to dissuade young smokers. We've seen this awareness begin to translate over to tobacco companies, including Altria , which has reduced its workforce by 15% amid falling cigarette volumes and stagnant sales for its premium Marlboro brand.

  • Alcohol use: Excessive alcohol use has the potential to raise your blood pressure and potentially even your cholesterol, thus increasing your chance of having a stroke. As is usually the case, moderation is the key to ensuring that alcohol use doesn't turn into abuse.

  • Physical inactivity: There's no miracle that can fully prevent a stroke if you aren't able to exercise. People who are physically inactive are at higher risk of developing high blood pressure or high cholesterol, getting type 2 diabetes, and becoming overweight or obese. Exercise may not be the entire solution to the problem, but it certainly improves your chances of preventing a stroke.

Hereditary factors
Just as we witnessed with certain cases of cancer and diabetes, sometimes genetic factors predetermine you to have an increased chance of having a stroke.

  • Family history of stroke: Unsurprisingly, both having had a stroke previously and having had a history of stroke in your family put you at a greater risk of having a stroke. According to a 2003 study conducted in Utah on stroke victims, 86% of all strokes occurred within just an 11% subset of families. These families would certainly appear to benefit from taking preventative lifestyle measures such as proper diet and exercise, as well as regular screenings to monitor cholesterol, blood pressure, and blood sugar levels.

  • Age and sex: Another factor unlikely to surprise you is that your risk for having a stroke increases as you get older. What is noteworthy is that men are considerably more likely to have a stroke than women, according to data from the National Institutes of Health. While everyone should be eating right and exercising, this is all the more reason for our aging baby boomer population to stay active.

  • Ethnicity: The final factor to determine stroke risk is race. Statistics have shown that Hispanics, African Americans, and American Indian/Alaska Natives have a considerably higher propensity to have a stroke than other ethnicities.

The takeaway
I believe the first important takeaway here is that a vast majority of these medical and behavioral conditions can be mitigated through simple lifestyle changes. This doesn't mean a life spent running 50 miles a day and eating nothing but turnips, but a proper diet and consistent exercise could go a long way to preventing high cholesterol, obesity, diabetes, and high blood pressure all in one fell swoop.

Also, understanding whether you're at risk and paying attention to the symptoms associated with stroke are crucial to treating a stroke should you have one.

A final aspect we've uncovered is that the treatment options available are greatly improving. We've had diabetes treatments available for decades, but only recently had J&J's Invokana been approved by the FDA. Invokana is opening up a swath of new potential treatments for diabetes sufferers that could increase weight loss while improving glycemic balance and reducing hypertension. Similarly, Belviq and Qsymia offer chronically obese patients a boost to assist them in their efforts to lose weight where diet and exercise alone haven't been as successful as they desired in the past.

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Fool contributor Sean Williams has no material interest in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.The Motley Fool owns shares of, and recommends, Johnson & Johnson. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.

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