burning of tobacco generates approximately 4000 compounds. The
smoke can be separated into gas and particulate phases. The composition
of the smoke delivered to the smoker depends on the composition
of tobacco and how densely it is packed, the length of the column
of tobacco, the characteristics of the filter and the paper, the
temperature at which the tobacco is burned.
gaseous phase components are carbon monoxide, carbon dioxide,
nitrogen oxides, ammonia, volatile nitrosamines, hydrogen cyanide,
volatile sulfur containing compounds, volatile hydrocarbons, alcohols
and aldehydes and ketones. Some of these compounds inhibit ciliary
movement in the lungs. Tar is the compound in tobacco that remains
after the moisture and nicotine are subtracted and consists of
polycyclic aromatic hydrocarbons, which are carcinogens. Non-volatile
nitrosamines and aromatic amines play an etiologic role in bladder
cancer. The actual content of nicotine in tobacco can vary from
0.2% to 5%.
Different forms of spit tobacco
exists as: loose leaf tobacco which is placed in foil pouches
and placed between cheek and lower gum where it is sucked and
chewed; snuff, which is moist or dry powdered tobacco is sold
in small round containers. The use of snuff is referred to as
"dipping" which involves leaving a pinch of tobacco
between the cheek and the lower gum. Chewing tobacco and snuff
are two types of smokeless tobacco products that are commonly
referred to as "spit tobacco." Compressed tobacco is
used in pieces and each piece is called a "plug." The
user bites off a small piece and places in the mouth. Nicotine
gum is another form of oral nicotine intake mainly used by individuals
who are trying to quit smoking.
products compared with cigarettes
pinch of snuff has the same effects as smoking three or four cigarettes.
The possibility of getting oral cancer increases significantly
for individuals who use SLT on a daily basis for 3.5 years or
longer. Continued use of SLT can cause cancer of the pharynx and
esophagus. Long-term snuff users have a 50% greater risk of developing
oral cancer than non-users. There is also severe inflammation
of gum tissue, tooth decay, and tooth loss associated with the
use of SLT. The Comprehensive Smokeless Tobacco Health Education
Act of 1986 was enacted by the Congress and required the rotation
of three health warnings on SLT packages and advertisements and
bans SLT advertising on broadcasting media.
composition of nicotine
is the most abundant of the volatile alkaloids in the tobacco
leaf. Nicotine is a colorless, and volatile liquid alkaloid found
in smoking and smokeless tobacco which turns brown and acquires
the odor of tobacco upon exposure to air. The alkaloid is water-soluble
and forms water-soluble salts.
of nicotine occur as a result of both stimulant and depressant
actions on various central and peripheral nervous system pathways.
This drug can increase the heart rate by excitation of the sympathetic
nervous system, or by paralyzing the parasympathetic nervous system.
Nicotine affects the medulla in the brain to increase heart rate.
Nicotine causes a discharge of epinephrine from the adrenal medulla,
which causes an increase in heart rate and raises blood pressure.
effects of nicotine
nicotine can stimulate the brain at all levels, significantly
increase breathing, lower HDL ( the good fats) levels, increase
blood pressure and constrict peripheral blood vessels.
experience nausea and vomiting, decreased urinary flow, increased
free fatty acids. Nicotine increases the oxygen requirements of
the heart muscle, but lowers oxygen supply, and this effect may
lead to heart attacks. Nicotine initially stimulates the salivary
and bronchial secretions and then inhibits them. Cigarette smoke
causes the excessive saliva associated with smoking. Nicotine
inhibits hunger and also causes a slight increase in blood sugar,
and deadens the taste buds. Smokers often report weight gain and
appetite increase after quitting smoking.
effects of nicotine
is a highly addictive drug. More than 24 billion packages of cigarettes
are purchased annually in the United States and approximately
400,000 deaths are attributed to cigarette smoking. Nicotine is
so addictive that approximately 70% of smokers who want to quit
smoking cannot and about 83% of smokers smoke every day. Smokers
report that cigarettes help them to relax. Nicotine is a cholinergic
agonist and stimulates the brain. Smokers experience withdrawal
symptoms when trying to quit smoking.
between tobacco use and chronic illnesses
A dose response
relationship exists between the number of cigarettes smoked per
day and particular illnesses. Men who smoke two packs of cigarettes
per day have a four time higher risk of developing chronic bronchitis
or emphysema than nonsmokers.
In the long
run lung tissue is damaged leading to emphysema. Cigarette smoking
also increases the risk of cardiovascular disease and smoking
is a major risk factor for heart attacks. The probability of heart
attack is related to the amount smoked, which has a synergistic
relationship to other risk factors such as obesity. Smoking is
a major risk factor for arteriosclerotic disease and aneurysm.
A direct relationship
(in men and women) has been found between amount of cigarettes
smoked and the development of lung cancer
The risk for
developing lung cancer increases:
* with the
* duration of smoking
* age at which person started to smoke
* degree of inhalation
* tar and nicotine levels of the cigarettes.
also exists between smoking and cancers of the oral cavity, esophagus,
urinary bladder, kidneys and pancreas. Cigarette smoking is the
leading cause of bronchopulmonary disease. Respiratory infections
are also more prevalent and more severe among smokers than nonsmokers.
Lower birth weight and survival rate of infants born to women
who smoke during pregnancy is a major concern. Infants born to
mothers who smoke are more likely to die from sudden infant death
syndrome (SIDS). Long term effects been observed in their physical
growth, mental development and behavioral characteristics.
is nicotine metabolized
is absorbed from the respiratory tract, and through mouth tissue
and skin. Approximately 80% to 90% of nicotine is metabolized
in the liver, kidneys and lungs. The lungs metabolize a major
portion of inhaled nicotine. The major metabolites of nicotine
are cotinine and nicotine. The half-life of nicotine after inhalation
or injection administration is about 2 hours. The kidney eliminates
both nicotine and its by-pruducts. The rate of urinary excretion
of nicotine is dependent on the pH (acidity) of the urine. Excretion
is reduced when the urine is alkaline. Nicotine is also excreted
in the milk of lactating women who smoke. Mammary milk of heavy
smokers may contain 0.5 mg of nicotine per liter of milk.
uses of nicotine
cigars and spit tobacco have no role in clinical medicine. Nicotine
chewing gum (nicorette)may be useful for individuals who are trying
to quit smoking.
of nicotine on athletic performance
participating in an NCAA survey (2001) reported using spit tobacco
for recreational or social purposes, to deal with the stresses
of college athletics and to feel good. About 53% of the athletes
who use spit tobacco reported using it 1-5 times daily. The use
of nicotine in high doses is toxic and can cause nicotine poisoning.
Signs of nicotine
poisoning are vomiting, sweating, mental confusion, diminished
pulse rate, headache, breathing difficulty, respiratory failure
caused by muscle paralysis and death. Impaired oxygen transport
secondary to increases in carboxyhemoglobin. In many cases smoking
will increase breathing rate during submaximal exercise, and this
will reduce athletic performance.
of tobacco use in the United States
3000 young people become regular smokers. Every day 6000 teens
under 18 smoke their first cigarette. Every day more than 1000
adults die prematurely as a result of an adolescent decision (USDHHS,
1996). Tobacco is considered a major gateway drug. The majority
of heroin addicts initially begin using gateway drugs such as
alcohol or tobacco products. The use of gateway drugs leads to
the development of patterns of behavior that makes it easier for
an individual to try other drugs. Cigarette smokers are more likely
to use alcohol, marijuana, and cocaine than nonsmokers are.