Health Affects Of Smoking
About 442,000 people in the United States And Same Population In India
die each year from illnesses caused by cigarette smoking. Smoking accounts for
nearly 90 percent of lung cancer deaths. Additionally, smokers are at increased
risk for cancer of the larynx, oral cavity, esophagus, bladder, kidney, and
pancreas. While some negative health effects of smoking manifest slowly over
time, others can be measured almost immediately. Sticky brown tar leaves yellow
stains on fingers and teeth. Some of the inhaled tar is absorbed by lung cells,
causing them to die. Tar also damages the cilia in the upper airways that
protect against infection. Nicotine causes arteries to constrict, lowering skin
temperature and reducing blood flow to the hands and feet. Carbon monoxide
deprives the body of oxygen, binding to red blood cells in place of the oxygen
molecule and forcing the heart to pump more blood through the body.
One-third of smoking-related deaths are
caused by coronary heart disease or chronic airway obstruction. For
example, the nicotine in tobacco combines with carbon monoxide in
tobacco smoke to damage the lining of blood vessels and make blood platelets
stickier. Platelets form part of the damaging plaque buildup in artery walls
(see Arteriosclerosis). These effects in combination
contribute to the development of heart disease. Smoking also increases the risk
of stroke by 50 percent—40 percent among men and 60 percent among
women. Other research has shown that mothers who smoke give birth more
frequently to premature or underweight babies, probably because of a decrease in
blood flow to the placenta. Babies born to mothers who smoke during pregnancy
are also at increased risk for sudden infant death syndrome.
Cigar and pipe smoke contains the same toxic
and carcinogenic compounds found in cigarette smoke. A report by the National
Cancer Institute concluded that the mortality rates from cancer of the mouth,
throat, larynx, pharynx, and esophagus are approximately equal in users of
cigarettes, cigars, and pipes. Rates of coronary heart disease, lung cancer,
emphysema, and chronic bronchitis are elevated for
cigar and pipe smokers and are correlated to the amount of smoking and the
degree of inhalation.
Studies have found that cigarettes are
addictive because an unknown component of tobacco smoke appears to destroy an
important brain enzyme known as monoamine oxidase B (MAO B). The enzyme is vital
for breaking down excess amounts of dopamine, a
neurotransmitter that triggers pleasure-seeking behavior. Smokers
have decreased levels of MAO B and abnormally high levels of dopamine, which may
encourage the smoker to seek the pleasure of more tobacco smoke.
Even nonsmokers are at risk from smoking.
Recent research has focused on the effects of environmental tobacco smoke
(ETS)—that is, the effect of tobacco smoke on nonsmokers who must share the same
environment with a smoker. The United States Environmental Protection
Agency (EPA) estimates that exposure to ETS, which contains all the toxic
agents inhaled by a smoker, causes 3,000 lung cancer deaths and an estimated
35,000 deaths from heart disease per year among nonsmokers. Secondhand smoke can
aggravate asthma, pneumonia, and bronchitis, and impair blood
circulation.
The smoking habit and addiction to nicotine
usually begin at an early age. In the United States, more than 90 percent of
adults who smoke started by age 21, and nearly half of them were regular smokers
by the age of 18. Despite increasing warnings about the health hazards of
smoking and widespread bans on smoking in public places, smoking remains common
among teenagers and young adults. In 2001 surveys of students in grades 9
through 12 found that more than 38 percent of male students and nearly 30
percent of female students smoke. Although black teenagers have the lowest
smoking rates of any racial group, cigarette smoking among black teens increased
80 percent in the late 1990s. Advertisements aimed at a young audience are
largely blamed for this new generation of smokers.
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