Stroke quiz: Are you at risk?

People with high blood pressure have a risk for stroke that is four to six times higher than the risk for those without high blood pressure. A third of the U.S. population, about 50 million people, has blood pressure readings consistently higher than 140/90. However, treatment for high blood pressure can reduce the incidence of stroke by 38 percent and the stroke mortality rate by 40 percent.

Informally known as "the stroke belt," the southeastern section of the United States has the highest stroke mortality rate in the country. Three of these states — North Carolina, South Carolina and Georgia — have been dubbed the "buckle" on the stroke belt. These three states have stroke mortality rates nearly twice that of the rest of the country overall.

This increased risk could be due to geographic or environmental factors or to regional differences in lifestyle, including higher rates of cigarette smoking and a regional preference for salty, high-fat foods.

The stroke risk for men is 1.25 times that for women. But men tend to be younger when they have strokes, so they have a higher rate of survival.

The same types of blockages that cholesterol can cause in the arteries carrying blood to your heart can occur in the arteries feeding your brain. The main culprit in these blockages is the "bad" type of cholesterol, called low-density lipoprotein (LDL). To be safe, your LDL levels should be below 130. Levels higher than 160 greatly increase your stroke risk.

If you have already had a stroke or heart attack, you may need to lower your LDL cholesterol even further.

After high blood pressure, the second most powerful risk factor for stroke is heart disease — especially a condition known as atrial fibrillation, which is an irregular beating of the heart. This leads to an irregular flow of blood and the formation of clots that can travel to your brain and cause a stroke.

People with diabetes have three times the risk of stroke compared to people without diabetes. The risk appears to be highest in the fifth and sixth decade of life, and decreases after that. Many people with diabetes have other health problems, such as high blood pressure, which can amplify their risk for stroke.

Cigarette smoking nearly doubles your risk of having the type of stroke caused by a blockage in an artery. This deadly habit constricts arteries, making it easier for blockages to occur. Smoking also increases the levels of blood-clotting factors in your blood and weakens the walls of blood vessels in your brain, so they can leak.

While daily consumption of small amounts of alcohol may decrease your blood's tendency to clot, lowering the risk of stroke, heavy drinking can cause hemorrhages in the brain if the clotting factors go too low. A rebound effect occurs after binge drinking, so artery-blocking clots form much more easily.

Illicit drugs, such as cocaine and crack cocaine, reduce blood flow to the brain by as much as 30 percent. Rapid heart rates can produce clots, which are then trapped in constricted blood vessels in the brain. Other drugs — amphetamines, heroin and anabolic steroids — also constrict blood vessels, increasing the risk for stroke.

Marijuana decreases blood pressure and may interact with other risk factors — such as high blood pressure and cigarette smoking — to cause rapidly fluctuating blood pressure levels, which can damage blood vessels and increase the risk for stroke.

Injuries to the head or neck can damage the vessels inside your brain and increase your risk for stroke. Traumatic brain injury can cause bleeding inside the brain, leading to the same type of problems caused by strokes. A sudden and severe extension of the neck, called "beauty parlor syndrome," can be a contributing factor in strokes — particularly in young people.