Tobacco use is the leading preventable cause of disease, disability, and death in the United States. Between 1964 and 2004, cigarette smoking caused an estimated 12 million deaths, including 4.1 million deaths from cancer, 5.5 million deaths from cardiovascular diseases, 2.1 million deaths from respiratory diseases, and 94,000 infant deaths related to mothers smoking during pregnancy. According to the Centers for Disease Control and Prevention (CDC), cigarette smoking results in more than 400,000 premature deaths each year—about 1 in every 5 U.S. deaths.

How does Tobacco affect the brain?

Cigarettes and other forms of tobacco, including cigars, pipe tobacco, snuff, and chewing tobacco, contain the addictive drug nicotine. Nicotine is readily absorbed into the bloodstream when a tobacco product is chewed, inhaled, or smoked. A typical smoker will take 10 puffs on a cigarette over a period of 5 minutes that the cigarette is lit. Thus, a person who smokes about 1/2 packs (30 cigarettes) daily gets 300 “hits” of nicotine each day.

Upon entering the bloodstream, nicotine immediately stimulates the adrenal glands to release the hormone epinephrine (adrenaline). Epinephrine stimulates the central nervous system and increases blood pressure, respiration, and heart rate. Glucose is released into the blood while nicotine suppresses insulin output from the pancreas, which means that smokers have chronically elevated blood sugar levels.

Like cocaine, heroin, and marijuana, nicotine increases levels of the neurotransmitter dopamine, which affects the brain pathways that control reward and pleasure. For many tobacco users, long-term brain changes induced by continued nicotine exposure result in addiction—a condition of compulsive drug seeking and use, even in the face of negative consequences. Studies suggest that additional compounds in tobacco smoke, such as acetaldehyde, may enhance nicotine’s effects on the brain. A number of studies indicate that adolescents are especially vulnerable to these effects and may be more likely than adults to develop an addiction to tobacco.

When an addicted user tries to quit, he or she experiences withdrawal symptoms including powerful cravings for tobacco, irritability, difficulty paying attention, sleep disturbances, and increased appetite. Treatments can help smokers manage these symptoms and improve the likelihood of successfully quitting.

What other adverse effects does Tobacco have on health?

Cigarette smoking accounts for about one-third of all cancers, including 90 percent of lung cancer cases. In addition to cancer, smoking causes lung diseases such as chronic bronchitis and emphysema, and increases the risk of heart disease, including stroke, heart attack, vascular disease, and aneurysm. Smoking has also been linked to leukemia, cataracts, and pneumonia. On average, adults who smoke die 14 years earlier than nonsmokers.

Although nicotine is addictive and can be toxic if ingested in high doses, it does not cause cancer; other chemicals are responsible for most of the severe health consequences of tobacco use. Tobacco smoke is a complex mixture of chemicals such as carbon monoxide, tar, formaldehyde, cyanide, and ammonia—many of which are known carcinogens. Tar exposes the user to an increased risk of lung cancer, emphysema, and bronchial disorders. Carbon monoxide increases the chance of cardiovascular diseases. Smokeless tobacco (such as chewing tobacco and snuff) also increases the risk of cancer, especially oral cancers.

Pregnant women who smoke cigarettes run an increased risk of miscarriage, stillborn or premature infants, or infants with low birth weight. Maternal smoking may also be associated with learning and behavioral problems in children. Smoking more than a pack of cigarettes per day during pregnancy nearly doubles the risk that the affected child will become addicted to tobacco if that child starts smoking.

Secondhand smoke, also known as environmental tobacco smoke, consists of exhaled smoke and smoke given off by the burning end of tobacco products. According to CDC, approximately 38,000 deaths per year can be attributed to secondhand smoke. Nonsmokers exposed to secondhand smoke at home or work increase their risk of developing heart disease by 25 to 30 percent and lung cancer by 20 to 30 percent. In addition, secondhand smoke causes respiratory problems in nonsmokers, such as coughing, phlegm, and reduced lung function. Children exposed to secondhand smoke are at an increased risk for sudden infant death syndrome, acute respiratory infections, ear problems, and more severe asthma.

While quitting can be difficult, the health benefits of smoking cessation are immediate and substantial, including reduced risk for cancers, heart disease, and stroke. A 35-year old man who quits smoking will, on average, increase his life expectancy by 5 years.

Source courtesy of: The National Institute on Drug Abuse