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TOBACCO IN BRIEF
Overview
Tobacco, which comes primarily from the plant nicotiana tabacum, has been used for centuries. It can be smoked, chewed, or sniffed. Most tobacco is sold in the form of cigarettes, cigars and pipe tobacco (cigar and pipe tobacco is made from stronger darker tobacco).
When nicotine was isolated from tobacco leaves in 1828, scientists began studying its effects in the brain and body. This research eventually showed that, although tobacco contains thousands of chemicals, the main ingredient that acts in the brain and produces addiction is nicotine.
Researchers say that three out of four people who start smoking become confirmed addicts, and that 90 percent of those who try to quit each year fail. A major part of the reason is that nicotine is as addictive as cocaine and heroin, and even more habit-forming than alcohol, according to scientists who study addiction.
Some of the effects of nicotine include changes in respiration and blood pressure, constriction of arteries, and increased alertness. Many of these effects are produced through its action on both the central and peripheral nervous system. Smokers feel that tobacco helps relieve boredom and tiredness and also helps reduce stress and anxiety.
No threshold level of exposure to cigarette smoke has been defined but there is conclusive evidence to indicate that long-term (years) smoking greatly increases the likelihood of developing numerous fatal conditions. Cigarette smoke contains over 4,700 chemical compounds.
Smoking costs the United States approximately $150 billion each year in health-care costs and lost productivity.
History
The first record of tobacco smoking is from Mayan records from about 500 AD, although it is very likely that tobacco had been smoked for a long time before. It arrived in England in 1565 although it wasn't until 1586 that Sir Walter Raleigh brought a large amount back from the 'New World'. It was used at first purely for medical purposes, as it was thought that tobacco could cure almost everything. Cigarettes first arrived when British Troops arrived back from the Crimean War where the French and Turkish armies smoked tobacco rolled up in paper. When the automatic rolling machine was invented in 1881 it paved the way for cigarettes to be made on a huge scale. This was the start of the massive multinationals which produce the world's tobacco and cigarettes today. The first description of addiction to tobacco is contained in a report from the New World in which Spanish soldiers said that they could not stop smoking.
Mechanism of Action
Nicotine readily enters the body. When tobacco is smoked, nicotine enters the bloodstream through the lungs. When it is sniffed or chewed, nicotine passes through the mucous membranes of the mouth or nose to enter the bloodstream. Nicotine can also enter the bloodstream by passing through the skin. Regardless of how nicotine reaches the bloodstream, once there, it is distributed throughout the body and brain where it activates specific types of receptors known as cholinergic receptors.
Nicotine
Nicotine is a major psychoactive constituent of tobacco. It is found in cigarettes, chewing tobacco, cigars and pipe tobacco. Cigarettes contain .13 to 2.0 mg. per cigarette. 5 milligrams of nicotine a day is enough to cause addiction. Most users develop tolerance for nicotine and need greater amounts to produce a desired effect. Within 20 seconds after it hits the bloodstream, nicotine reaches the brain and is distributed among the trillions of neurons that govern thinking, memory, perception and emotion. At that point, it stimulates the production of a chemical messenger, called dopamine, that helps pass signals from one neuron to another. This excess of dopamine produces the pleasurable sensations that accompany smoking.
Nicotine has both stimulant and depressant effects on the central nervous system. It can cause a wide variety of symptoms, including the following:
· alertness or relaxation · changes in mood and behavior · diarrhea · increased pulse and blood pressure · nausea and vomiting · tremors
Triggers
People quickly become dependent on nicotine when using tobacco products. Anyone who uses these substances is at risk of experiencing withdrawal symptoms. A trigger is anything that creates an impulse to use tobacco. Triggers can be feelings, such as stress, anxiety, depression, or boredom. They can be visual, such as a picture of a poised glamorous movie star taking a long, seemingly satisfying drag. Triggers can even be certain times of the day, such as work breaks or meals.
Health Risks
The health risks from the chemicals found in tobacco are enormous. Cigarette smoking is perhaps the most devastating preventable cause of disease and premature death. Tobacco contains 200 known poisons that can damage health.
- Cigarettes contain at least 43 distinct cancer-causing chemicals. Smoking is directly responsible for 87 percent of lung cancer cases and causes most cases of emphysema and chronic bronchitis. Smoking is also a major factor in coronary heart disease and stroke; may be causally related to malignancies in other parts of the body; and has been linked to a variety of other conditions and disorders, including slowed healing of wounds, infertility, and peptic ulcer disease.
- Smoking in pregnancy accounts for an estimated 20 to 30 percent of low-birth weight babies, up to 14 percent of preterm deliveries, and some 10 percent of all infant deaths. Even apparently healthy, full-term babies of smokers have been found to be born with narrowed airways and curtailed lung function. Only about 30 percent of women who smoke stop smoking when they find they are pregnant; the proportion of quitters is highest among married women and women with higher levels of educational attainment. In 1999, 12.3 percent of women who gave birth smoked during pregnancy.
- Smoking by parents is also associated with a wide range of adverse effects in their children, including exacerbation of asthma, increased frequency of colds and ear infections, and sudden infant death syndrome. An estimated 150,000 to 300,000 cases of lower respiratory tract infections in children less than 18 months of age, resulting in 7,500 to 15,000 annual hospitalizations, are caused by secondhand smoke.
- Secondhand smoke involuntarily inhaled by nonsmokers from other people's cigarettes is classified by the U.S. Environmental Protection Agency as a known human (Group A) carcinogen, responsible for approximately 3,000 lung cancer deaths annually in U.S. nonsmokers.
Tobacco use can cause the following diseases:
- chronic bronchitis
- gastro esophageal reflux disease
- lung cancer
- coronary artery disease and other forms of heart disease
- emphysema
Tobacco also is a factor in causing the following conditions:
decreased life expectancy
erectile dysfunction, or impotence
gray hair and baldness
high blood pressure and circulation problems
infertility in men and women
osteoporosis and increased risk for bone fractures
premature wrinkles
weakened immune system
Risks to Others
Smoking is a form of air pollution. It exposes others to secondhand smoke. People who are exposed to a significant amount of secondhand smoke share many of the same risk factors as people who smoke. A pregnant woman who smokes increases her risk for miscarriage and other health problems for her baby. Smoking-related diseases claim an estimated 440,000 American lives each year, including those affected indirectly, such as babies born prematurely due to prenatal maternal smoking and some of the victims of "secondhand" exposure to tobacco's carcinogens.
Short-term problems from tobacco:
- Diminished or extinguished sense of smell and taste
- Frequent colds
- Smoker's cough
- Increase in heart rate and blood pressure
- Physiological stress and anxiety
Potential problems associated with the regular use of tobacco:
- Emphysema
- Heart disease
- Gastric ulcers
- Bronchitis
- Heart disease
- Stroke
- Cancer of the mouth, larynx, pharynx, esophagus, lungs, pancreas, cervix, uterus, and bladder
- Premature and more abundant face wrinkles
Who Smokes?
Smokers make up well over 10% of the general population - perhaps as much as 30%, according to recent studies.
- Approximately 22.2 million American women are smokers. Current female smokers aged 35 years or older are 12 times more likely to die prematurely from lung cancer than nonsmoking females. More American women die annually from lung cancer than any other type of cancer; for example, lung cancer will cause an estimated 65,700 female deaths in 2002, compared with 39,600 estimated female deaths caused by breast cancer.
- As smoking has declined among the White non-Hispanic population, tobacco companies have targeted both African Americans and Hispanics with intensive merchandising, which includes billboards, advertising in media targeted to those communities, and sponsorship of civic groups and athletic, cultural, and entertainment events.
- The prevalence of smoking is highest among Native Americans/Alaskan Natives (40.89 percent), next highest among African Americans and whites (24.3 percent), followed by Hispanics (18.1 percent) and Asians and Pacific Islanders (15.1 percent).
- Tobacco advertising plays an important role in encouraging young people to begin a lifelong addiction to smoking before they are old enough to fully understand its long-term health risk. It is estimated that 4.5 million U.S. teenagers are cigarette smokers; 22.4 percent of high school seniors smoke on a daily basis. Approximately 90 percent of smokers begin smoking before the age of 21.
Withdrawal from tobacco
Smokers become physically and psychologically dependent and will suffer withdrawal symptoms including: changes in body temperature, heart rate, digestion, muscle tone, and appetite. Psychological symptoms include: irritability, anxiety, sleep disturbances, nervousness, headaches, fatigue, nausea, and cravings for tobacco that can last days, weeks, months, years, or an entire lifetime.
The material in this article is provided for informational purposes only. For specific medical advice or diagnosis, consult a healthcare provider.
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