Cigarettes
damage the body--gradually and insidiously--in a number of different
ways. Over the years, the American Council on Science and Health and
others have documented the effects. One popular argument the scientific
community often makes to encourage smokers to quit stems from the
conjecture that all of the health effects of smoking are reversible
shortly after cessation, regardless of the duration or intensity of the
smoking exposure. Unfortunately, this conjecture is not true. Teenagers,
in particular, may be overly complacent about smoking because they
believe--incorrectly--that they can smoke for a few years and then quit
without suffering any long-term effects. This complacency is especially
troubling in light of the recent finding, reported by the Centers for
Disease Control and Prevention (CDC) that teen smoking rates have
increased by nearly a third within the last six years.
Teen
smokers who believe that all the health hazards of cigarettes will
disappear in a puff of smoke when they quit--who assume that smoking
from, say, age 16 to age 28 will have no long-term effects--often fall
back on an "I can always quit tomorrow" (or next month or next year)
philosophy. They trust--mistakenly--that any adverse health consequences
they may incur during their smoking years will disappear when,
eventually, they stop lighting up. But another recent study has reported
that the quitting success rate among teenagers is very low: Less than
16 percent of the 633 teen smokers in the study were able to kick the
habit.
Cigarettes and Public Health
Cigarette
smoking is the leading cause of preventable death in the United States.
It accounts for almost 500,000 deaths per year, or one in every five
deaths. Cigarette smoking contributes to a remarkable number of
diseases, including coronary heart disease, stroke, chronic obstructive
pulmonary disease, peripheral vascular disease, peptic ulcer disease,
and many types of cancer. Of the 46 million smokers in the United
States, 34 percent try to quit each year--but less than 10 percent
succeed. According to the CDC, approximately 80 percent of current adult
smokers began smoking before their 18th birthday. Each day over 3,000
teenagers light up for the first time. Most teens are aware of smoking's
hazards, but few are worried about them. Moreover, most teen smokers
quickly become addicted to nicotine: They report that they want to quit
but are unable to do so. And teen smokers experience high relapse rates
and debilitating withdrawal symptoms. The bottom line is that smoking is
costly, both to individual smokers and to society as a whole: Recent
long-term studies indicate that about half of all regular cigarette
smokers will eventually die from their addiction.
A study of
civilians was conducted by Dr. Petter Lundborg, an economist at the Free
University of Amsterdam. Lundborg examined data on a nationally
representative sample of 14,272 workers, ages 16 to 65, in Sweden.
Lundborg analyzed sick days taken between 1988 to 1991 using information
from a social insurance database. He found smokers averaged 34 sick
days annually, compared to 25 sick days a year for former smokers and 20
for nonsmokers. In his analysis, Lundborg controlled for health
problems among all participants and found health problems were not the
only cause of smokers' absenteeism. "I found that health problems
accounted for about two days and something," said Lundborg. "The
remaining eight days are probably explained by something other than
health. There are a number of possible explanations for the difference,"
he said, "There might be personal characteristics that we can't
observe." Likewise, Conway and fellow researchers in a study of women in
the U.S. Navy noted "Cigarette smoking might simply be a 'marker' for
other underlying factors (e.g., non-conformity, high risk-taking) that
contribute to poorer performance in the military."
Conway and
colleagues examined data on 5,487 women who enlisted during a one-year
period beginning in March 1996. "Compared with never-smokers, daily
smokers at entry into the U.S. Navy had subsequent career outcomes
consistently indicating poorer job performance (e.g., early attrition
prior to serving a full-term enlistment, more likely to have a
less-than-honorable discharge, more demotions and desertions, lower
achieved pay-grade and less likely to re-enlist)," they wrote.
"Tobacco
use is of particular concern to the U.S. Department of Defense because,
historically, the military has had higher and heavier rates of tobacco
use than civilians," wrote the researchers. The Pentagon health survey
found, among members of the U.S. military, smoking increased from 30% in
1988 to 34% in 2002 -- the first recorded rise since 1980.
Among
the U.S. population in general, smoking has steadily decreased since
1965. In 1965, 42.4% of American adults were smokers, compared to 20.9%
in 2004. This decline began after the Surgeon General's first report on
the dangers of smoking in 1964. This warning could have been made
earlier -- in 1957 and again in 1959 then-Surgeon General Leroy Burney
was the first federal officer to publicly state smoking was a cause of
lung cancer.
Chemicals in Cigarette Smoke
Chemicals in Cigarette Smoke
Here
is a partial list of the chemicals in commercially manufactured
cigarettes. The first part lists chemicals known to cause cancer, called
carcinogens:
Dimethylnitrosamine
Ethylmethylnitrosamine
Nitrosopyrrolidine
Hydrazine
Vinyl Chloride
Urethane
Formaldehyde
Other Toxic Agents:
Carbon
Monoxide, Hydrogen Cyanide, Acrolein, Acetadehyde, Nitrogen oxides,
Ammonia, Pyridine, Nitric acid, Mathylamine, Hydrogen cyanide, Indole,
3-hydroxypyridine, 3-vinylpyridine, Acetone, Acetonitrile, Acrolein,
1,3-Butadiene, mg, Nitrous acid, isoquioline, Isoamylamine,
3-Cyanopyridine.
This is only a partial list. They put these
chemicals in cigarettes to reduce tar while maintaining the level of
nicotine necessary to keep them addictive. Keeping the tar down helps to
calm people's fears about health risks. Since the companies are free of
any supervision they are not compelled to reveal the chemicals they
use. But recent breaks in the wall of secrecy have revealed that
cigarettes are only about 40% tobacco, and 60% other junk.
Secondhand Smoke
Smokers
scorn nonsmokers' disgust for cigarette smoke, saying they're just
"jumping on the bandwagon," or being PC, or being fussy wimps. Here's
the point: Cigarette fumes contain harmful chemicals. That is why being
trapped in cigarette smoke is not like being trapped in a portable
toilet. It's not the smell, it's the instantaneous physical, somatic
reactions. It's like the difference between the air in a barnyard and
the air in an unventilated garage with an idling diesel bus. The first
is merely unpleasant, the second is poisonous. The physical reaction
(sweaty palms, nausea, headache) all warn of danger, and urge whoever to
get into some fresh air immediately.
In days of old canaries
were kept in coal mines, because if there was coal gas in the air, the
canaries would die more quickly than the miners, alerting them to the
danger. Coal gas and cigarette smoke are both inescapable when they
permeate the local air. And it didn't take government studies to come to
this conclusion. Non-smokers have always sensed it, but had no
corroborating evidence, until now. Here's the latest information from
the U.S. Occupational Safety and Health Administration.
Component (Known or probable carcinogens)
|
How much more is in sidestream smoke
|
| Polonium-210 |
1 to 4 times
|
| Benzo[a]pyrene |
2.5 to 3.5 times
|
| Hydrazine |
3 times
|
| 1,3 butadiene |
3 to 6 times
|
| Benzene |
5 to 10 times
|
| N-nitrosopyrrolidine |
6 to 30 times
|
| Cadmium |
7.2 times
|
| Nickel |
13 to 30 times
|
| N-nitrosodimenthylamine |
20 to 100 times
|
| Aniline |
30 times
|
| 2-Naphthylamine |
30 times
|
| 4-Aminobiphenyl |
31 times
|
| N-nitrodiethylamine |
up to 40 times
|
Irreversible Health Effects
With
smoking, the reversibility of health effects is influenced by many
factors. Among those factors are smoking exposure (the number of
cigarettes per day and the duration of smoking) and physiologic
susceptibility. The presence of other diseases, genetic variables, and
even nutritional factors also enter into susceptibility assessment.
Quitting brings benefits at any age, but there are "threshold" amounts
of smoking that irreversibly increase the risk for some diseases.
The
good news is that quitting prolongs life and reduces the risk of
tobacco-related cancers, myocardial infarction, cerebrovascular disease,
and chronic obstructive pulmonary disease (COPD). Current knowledge of
the irreversible effects of smoking, organized by organ systems,
follows.
Respiratory System
Smoking
directly irritates and damages the respiratory tract. Each year a
one-pack-a-day smoker smears the equivalent of a cup of tar over his or
her respiratory tract. This irritation and damage cause a variety of
symptoms, including bad breath, cough, sputum production, wheezing, and
respiratory infections such as bronchitis and pneumonia. These effects
can be reduced, but not entirely reversed, by quitting.
Smoking
is the principal risk factor for developing COPD--i.e., chronic
bronchitis and emphysema. Emphysema is characterized by permanent
structural changes in the lung tissue. The deterioration in lung
function associated with COPD is directly related to duration of smoking
and the number of cigarettes smoked ("pack-years"). Smoking during
childhood not only increases the risk of developing COPD in adulthood
but also lowers the age of its onset. Cigarette smoking during childhood
and adolescence increases the number and severity of respiratory
illnesses. It also causes retardation in the rate of lung development
and in the level of maximum lung function--and retardation in lung
growth during childhood means that the lungs may never attain normal
function and development.
Everyone--smoker and nonsmoker
alike--experiences a slow decline in lung function starting at about age
30. In smokers this gradual decline starts both from a lower baseline
and at an earlier age. Smokers suffer from decreased lung reserve: They
are unable to run--or even walk--as far or as fast as their peers who
have never smoked. Smokers thus can expect permanently impaired lung
function relative to their nonsmoking peers. With sustained abstinence
from smoking, the rate of decline in pulmonary function among smokers
returns to normal; but lung reserve remains decreased relative to those
who have never smoked. Quitting improves pulmonary function by about 5
percent within a few months of cessation, and COPD mortality rates
decline among quitters versus continuing smokers. A recent study in more
than 10,000 boys and girls aged 10 to 18 confirmed that cigarette
smoking is associated with mild airway obstruction and slowed growth of
lung function. The study, which covered a period of 15 years, also
demonstrated that girls are more susceptible than boys to smoking's
adverse effects on the growth of lung function. Smoking-induced chronic
irritation of the respiratory lining and the wide variety of carcinogens
in cigarette smoke induce permanent changes in the cells lining the
respiratory tract. These changes can lead to cancer.
Cigarette
smoking is, in fact, the major cause of lung cancers of all major
histologic types. During the past half century, lung cancer rates have
dramatically increased in women, to the extent that lung cancer is now
the leading cause of cancer death in women, exceeding both breast cancer
and colon cancer. (Smoking has, of course, been the leading cause of
cancer death in men for decades.) This increased female mortality
parallels the increase in cigarette smoking among women.
Smoking
cessation reduces lung cancer risk by 30 percent to 50 percent 10 years
after quitting, and the risk continues to decline with further
abstinence. The risk in ex-smokers always remains increased compared to
that in nonsmokers, however. It is now known that almost 50 percent of
all lung cancers are diagnosed in ex-smokers, and this finding is not
surprising in view of the fact that there exist a "plethora of studies
demonstrating a lag between smoking initiation and increased incidence
of lung cancer of several decades."
One recent study noted that
75 percent of ex-smokers showed changes in their DNA indicative of
precancerous lesions, as compared to only 3 percent of people who had
never smoked. At the May 1998 meeting of the American Lung Association,
data were presented showing that former smokers continued to develop
lung cancer at rates 11 to 33 times higher than nonsmokers. The data
also showed that the shorter the time since quitting, the higher was the
ex-smoker's risk. Increased risk was still noted in former smokers
after more than 20 years of abstinence, however.
Heart and Circulation
Premature
coronary heart disease (CHD) is one of the most important medical
consequences of smoking. Smoking acts both independently of and
synergistically with other major risk factors for heart disease. Sadly,
sudden death may be the first sign of CHD--and sudden death is four
times more likely to occur in young male cigarette smokers than in
nonsmokers. Women who use both cigarettes and oral contraceptives
increase their risk of developing CHD tenfold. The excess risk of
coronary heart disease is halved in quitters (as compared to continuing
smokers) one year after cessation, but the risk level doesn't return to
that of nonsmokers until 15 years after quitting. In a recent study of
atherosclerosis, the progression of fatty deposits in the carotid artery
was found to be dependent on total pack-years of tobacco exposure,
rather than on the patient's current smoking status. This finding
indicates that atherosclerosis progression may also be cumulative and
irreversible, at least after some degree of baseline exposure.
Cerebrovascular
accident (CVA), or stroke, causes brain damage that usually leaves its
victims with permanent disabilities. Smokers' excess risk for stroke
appears to return to that of nonsmokers within 5 to 15 years of
cessation. One recent study suggests, however, that an ex-smoker's risk
remains high for at least 20 years after cessation. In addition, it was
recently learned that the incidence of "silent strokes"--events that are
harbingers of both severe strokes and dementia--is increased in anyone
who has ever smoked.
Finally, smoking is a strong risk factor for
several types of blood-vessel disease. Smoking causes poor circulation
to the legs by narrowing the blood vessels that supply these
extremities. Quitting reduces, but does not eliminate, this risk. Once
it becomes symptomatic, such circulatory impairment often requires
surgical intervention.
Eyes and Vision
Two
recent studies published in the Journal of the American Medical
Association tracked 50,000 smokers for approximately 12 years. The
studies found a two- to three-fold increased rate among both smokers and
ex-smokers of developing macular degeneration, an irreversible form of
blindness. The risk was significant even among those who had quit
smoking 15 or more years earlier. Researchers speculate that smoking
causes vision loss by restricting blood flow to the eye. Cataracts
(clouding of the lens) are another visual problem associated with
cigarette smoking. A recent study showed a 40-percent higher rate of
cataracts among 3,600 people who had ever smoked, as compared to
nonsmokers.
Mouth and Throat
Cigarette
smoke irritates the eyes, nose, throat, and gums. These tissues respond
by thickening and by undergoing cellular changes that can eventually
lead to mouth, throat, or esophageal cancer. Gum disease and tooth loss
are also common among smokers. Quitting halves the risk for cancers of
the oral cavity and esophagus during the first five years after
cessation, but ex-smokers always have an increased risk as compared to
the risk in those who have never smoked. Cigarette-smoke irritants can
also permanently damage the tissues of the larynx. The effect of this is
a noticeable deepening and hoarseness in the voices of chronic smokers.
Quitting reduces the risk of developing laryngeal cancer. Vocal-cord
polyps (non-cancerous growths) are also strongly related to tobacco
exposure, and such polyps rarely disappear without surgery.
Genito-Urinary Tract
Smoking
causes bladder and kidney cancer. It is, in fact, the strongest risk
factor known for developing bladder cancer. An ex-smoker's risk of
bladder cancer is reduced by one half within a few years after quitting,
but a higher risk of developing these cancers remains for decades.
Digestive Organs
Smoking
decreases esophageal sphincter pressure. The decrease in pressure
allows acid to reflux from the stomach into the esophagus. This can lead
to esophagitis and to permanent esophageal stricture (or narrowing).
Smoking is also a risk factor for pancreatic cancer and colon cancer.
The risk of pancreatic cancer is somewhat reduced 10 years after
quitting; ex-smokers remain at higher risk indefinitely, however. The
relationship between cigarette smoking and colon cancer has only
recently become clearer. Two large, prospective American studies have
detected such a relationship, but a recent Swedish study detected no
such relationship in smokers observed for 20 years. The American
researchers felt that it might take as long as 35 years for the colon
cancers secondary to smoking to appear: In a study that looked at a
large group of people who had smoked for as few as 10 years, the
American researchers detected progressively more severe colonic lesions
with increasing time after quitting.
Musculoskeletal System
Smoking
is associated with osteoporosis (thinning of the bones due to loss of
bone minerals) in women, and with spinal disk disease in both sexes.
Lost bone calcium cannot be fully recovered, and degenerative bony
changes are irreversible. Osteoporosis predisposes to fractures and is
responsible for much disability, especially in elderly women. A recent
meta-analysis of 29 studies involving almost 4,000 hip fractures
concluded that one of every eight fractures was attributable to smoking,
although the rate was lower for ex-smokers than for current smokers.
Reproduction
Infertility
is more common among smokers but is not irreversible. The damage done
to smokers' babies during pregnancy often is irreversible, however.
Smoking during pregnancy is associated with dire consequences for the
baby as a fetus, as a newborn, and even as a child. Recognition of the
evidence of this damage has prompted researchers to designate it as
"fetal tobacco syndrome." Miscarriage is two to three times more common
in smokers, as are stillbirth due to fetal oxygen deprivation and
placental abnormalities induced by the carbon monoxide and nicotine in
cigarette smoke. Smokers have a fourfold risk of having a low
birthweight baby; such babies are more likely than normal-weight babies
to have impaired physical, emotional, and intellectual development.
The
authors of a 1996 study found that women who smoked during pregnancy
were 50 percent more likely to have a child with mental retardation of
unknown cause than were nonsmoking women. Sudden infant death syndrome
is significantly associated with smoking, as is impaired lung function
at birth. Women who quit smoking as late as the first trimester may
diminish some of these risks, but the risk of certain congenital
malformations--such as cleft palate--is increased even in women who quit
early in pregnancy.
The Skin
Smoking
causes premature facial wrinkling through vasoconstriction of the
capillaries of the face (vasoconstriction decreases the flow of oxygen
and nutrients to facial skin cells). The effect of this reduced blood
flow is visible in deep crow's feet radiating from the corners of the
eyes and pale, grayish, wrinkled skin on the cheeks. These effects may
emerge after as few as five years of smoking and are largely
irreversible, except through costly and traumatic facial surgery.
Conclusion
There
should be no illusions as to the dangers of cigarettes. The combination
of a highly addictive, pharmacologically active
substance--nicotine--and an array of noxious chemicals cunningly
packaged in a highly efficient delivery mechanism can permanently and
drastically affect health. People who smoke for as brief a period as 10
years, show a substantially higher rate of death, disease, and
disability. Risks to the respiratory system, especially, and risks of
cancer continue to plague the ex-smoker for years after quitting.
Smokers should not delude themselves that they can smoke safely for 10
to 15 years and then--if they are among the lucky few who can
quit--become as healthy and risk-free as if they had never smoked at
all. The risks faced by smokers are well-documented; for a truly
comprehensive guide to those risks, see the groundbreaking ACSH book,
Cigarettes: What the Warning Label Doesn't Tell You.
In summary, the following irreversible health effects have been proven to be associated with smoking:
*
Retardation in the rate of lung development and lung function--i.e.,
decreased lung reserve--in childhood and adolescent smokers, as well as a
markedly increased risk of developing COPD.
* Cancer risk: 75
percent of ex-smokers show DNA changes suggestive of tumor development;
50 percent or more of lung cancers are now being diagnosed in
ex-smokers.
* Circulatory impairment to the heart, brain, and legs.
* Visual impairment and loss.
* Vocal-cord polyps (growths) and hoarseness.
* Bone mineral loss (osteoporosis), hip fractures, and spinal arthritis.
* Serious health consequences for children born to smoking mothers.
* Premature facial wrinkling and graying of the skin after as few as five years of smoking
