Smoking is the leading cause of preventable death in the world. According to the CDC, diseases caused by smoking kill more than 480,000 people in the United States. each year. The CDC also states that smokers are 2 to 4 times more likely to develop heart disease and stroke. Despite the known dangers, many people continue to smoke or start smoking every year. One out of 5 deaths of Americans is related to smoking, and it kills more Americans each year than suicides, homicides, AIDS, and car accidents combined.

Smokers not only have an increased risk for lung disease, including lung cancer and emphysema, but also have an increased risk for heart disease, stroke, and oral cancer. Almost one-third of all cancers are related to smoking. Smoking kills more women each year than breast cancer. Smoking also contributes to the development of diabetes, tuberculosis, immune system disease, and male impotence.

In posing health risks to the body's cardiovascular system, smoking:

• Causes immediate and long-term increases in blood pressure.
• Causes immediate and long-term increases in heart rate.
• Reduces cardiac output and coronary blood flow.
• Reduces the amount of oxygen that reaches the body's tissues.
• Changes the properties of blood vessels and blood cells, allowing cholesterol and other fatty substances to build up.
• Contributes to an increased risk for blood clot formation.
• Damages blood vessels.
• Doubles the risk for ischemic stroke (reduced blood flow to the brain).

Smoking has also been linked to depression and psychological distress.

Secondhand smoke is smoke that is exhaled by smokers and smoke emitted from the burning end of a lit cigarette, cigar, or pipe. Secondhand smoke has immediate harmful effects on the heart and blood vessels and can also cause lung cancer and stroke.

Both direct and indirect smoking exposure poses significant health hazards to pregnant women, infants, and young children. Children and babies exposed to tobacco smoke are more likely to have ear infections and asthma, and are at a higher risk for SIDS (sudden infant death syndrome) than children and babies without the same exposure.

These common symptoms may be linked to exposure to secondhand smoke:

• Irritation of the eyes, nose, and throat
• Coughing
• Excessive mucus in the airways (phlegm)
• Chest discomfort from lung irritation
• Chest pain, which may mean heart disease

The symptoms of secondhand smoke exposure may look like other health conditions. Always see your doctor for a diagnosis.

Creating a smoke-free environment indoors and outdoors protects nonsmokers from secondhand smoke exposure.

Smoking is one of the main risk factors for heart disease. Other risk factors are high cholesterol, high blood pressure, physical inactivity, obesity, and diabetes. In fact, smoking is the single most preventable cause of premature death in the United States.

Eliminating smoking has both short-term and long-term rewards. Within weeks of quitting, blood pressure lowers and blood circulation improves. One year after quitting, the risk for heart disease from smoking decreases by 50%. Five years after quitting, your risk for certain cancers caused by smoking decreases by 50%. Research also shows that stopping smoking is key to managing the many contributors to heart attack. These include atherosclerosis, thrombosis, coronary artery disease, and cardiac arrhythmias.

Quitting smoking is both a mental and a physical undertaking. Mentally, you should be ready and fairly stress-free. Physically, you need to commit to exercising daily and getting plenty of sleep. You must overcome both a physical addiction to nicotine and a habit. Experts offer these tips to help users quit using tobacco products:

• Think about why you want to quit.
• Pick a stress-free time to quit.
• Ask for support and encouragement from family and friends.
• Start a daily exercise or activity to relieve stress and improve your health.
• Get plenty of rest.
• Eat a balanced diet.
• Join a smoking cessation program or other support group.

In some cases, smokers benefit from nicotine replacement products to help break their smoking habit. Nicotine replacement products continue to give smokers nicotine to meet their nicotine cravings. But the benefit of these products is that they don't have the tars and poisonous gases that cigarettes give off. Pregnant or nursing women and people with other health conditions should talk with their doctor before using any nicotine replacement products. Some examples of nicotine replacement products include:

• Nicotine chewing gum. An over-the-counter (OTC) chewing gum. It releases small amounts of nicotine to help reduce nicotine withdrawal symptoms.
• Nicotine patch. An OTC patch applied to the upper body once a day. It releases a steady dose of nicotine to help reduce the urge to smoke.
• Nicotine lozenge. An OTC lozenge that dissolves in the mouth. It releases small amounts of nicotine to reduce any cravings to smoke.
• Nicotine inhaler. A prescription nicotine replacement product. It is inhaled through the mouth.
• Nicotine nasal spray. A prescription nicotine replacement product. It is sprayed into the nose.

Varenicline. This is also a non-nicotine pill to help with quitting smoking. It was approved by the FDA in 2006. It is the first medicine that targets the nicotine receptors in the brain. Varenicline attaches to the receptors and blocks nicotine from reaching them. This decreases the desire for nicotine. Varenicline may not be right for everyone. Talk with your doctor to see if this is a good choice for you.

Bupropion. This is a non-nicotine pill to help people stop smoking. It was approved in 1997 by the FDA. Bupropion has been shown to change mood transmitters in the brain that are linked to addiction. It must be prescribed by a doctor. Bupropion may not be right for everyone. Talk with your doctor for more information.

E-cigarettes are devices that create vaporized, heated nicotine-containing liquid that a person inhales into their lungs. This is also called vaping.

E-cigarettes are not approved by the FDA as a quit-smoking aid.

E-cigarettes may be harmful. They may have substances that can cause cancer. They have also been linked to severe lung disease. Some people have died from this. Experts are not sure exactly what has caused these illnesses. They don't seem to be caused by lung infections. But all of the people who developed these lung conditions had used e-cigarettes. Most people who became sick used e-cigarettes that contained the chemical THC. This is the main active ingredient in marijuana. Some people became ill after using e-cigarettes with both THC and nicotine. Others got sick after using only nicotine e-cigarettes. The CDC calls this EVALI (e-cigarette or vaping product use-associated lung injury). Experts don't know if people who have had EVALI are at higher risk for severe complications from the flu (influenza) or other viral lung infections. Doctors recommend a yearly flu shot for everyone over 6 months of age, including people who have had EVALI.

Because of these and other health risks, experts advise people not to use e-cigarettes.