According to world Health
Organization, about 1.3 billion smokers were present worldwide in 2003, and
there is an expectation that the number will increase to 1.7 billion by 2020.
Cigarette smoking is a great risk to the population because of vast multitude of
chemicals present in it. It is known that cigarette contains 599 chemicals and
there are over 4,700 chemical compounds in cigarette smoke which includes 40-60
compounds known as carcinogens. It is very difficult to give all the toxic
compounds that are present in cigarette but some carcinogens include Polycyclic
Aromatic Hydrocarbons (PAH), N-nitrosamines compounds, Aromatic Amines and Trace
metals. Among trace metals, cadmium, nickel, arsenic and polonium are mostly
present. There are evidences that cigarette smoke also contains some bacteria,
molds and microbial toxins (exotoxins and endotoxins) linked to the inflammation
of lungs.
Cigarette smoke is divided into two groups, one is called mainstream smoke and
other is called as side stream smoke. The chemical composition of these two
smokes is mainly similar but difference exists in quantities of compounds that
are present in them. Side stream smoke contains more compounds as compared to
mainstream so it possess more risk to smoker than main stream smoke because it
is more toxic. Inhalation of fresh side stream smoke is somewhat four times more
toxic than main stream smoke. The compounds after burning appear in two phases,
gas phase in the form of aerosols and solid phase as tar. There is 300 to 500
ppm of nitric oxide in fresh main stream and side stream cigarette smoke which
converts into nitrogen dioxide. The most commonly known ingredients of cigarette
are nicotine, tobacco (an addictive toxicant) and tar. Other poisonous
ingredients are carbon monoxide, hydrogen cyanide, DDT and naphthalene. Besides
the negative impacts of nicotine which is a major component of cigarette
composition, it also has a neuroprotective effect. It is found that cigarette
smoke contains a number of tumor initiating and tumor promoting agents who may
provide a favorable environment for the development of cancer. The mixture of
different kind of chemicals in cigarette smoke has a potential to affect almost
every organ system in the body because of sufficient duration of exposure. The
extent and timing of exposure is very important while assessing the toxicity of
smoking. It is inferred by the research that smoking for 45 years causes 100
times more risk of lung cancer than the risk to people who had been smoking for
15 years, irrespective of the heavy or moderate doses taken.
Worldwide, the death rate of 20% is due to tobacco use which is an important and
main constituent of cigarette composition. Study shows that long-term smoking
greatly increases the chance of developing many other fatal conditions. Smoking
affects all the systems of the body mainly including digestive and respiratory
systems. Among the most problematic conditions developed in digestive tract due
to cigarette smoking is decreased flow of blood to intestine, backflow movement
of stomach acid from stomach to esophagus causing heartburn, damage to liver
which is the main filter organ of the body. Smoking may also cause ulcer which
may often become fatal . In UK one out of four cancer deaths are related to
smoking. It causes five times more deaths than road accidents and other
incidences.
Smoking is a principal cause of cancer and as well as death from cancer.
Carcinogens that are present in inhaled cigarette smoke damage the DNA and
promote uncontrolled cell growth that might be invades to the other body cells
and in this way causes cancer of many organs other than lungs. It is estimated
that more than 85% of lung cancers is associated with smoking. 90% of lung
cancer in men, and 80% in women are due to cigarette smoking. There is about 23
times more chances to develop lung cancer in men and about 13 times in women.
Approximately 171,900 new lung cancer cases occurred in 2003 and about 157,200
people died from lung cancer. Estimation shows that 57,400 new cases of bladder
cancer are due to smoking.
Cigarette smoking also causes cancers of the mouth, pharynx, larynx, esophagus,
stomach, pancreas, uterine cervix, kidney, ureter, bladder and colon. It is also
linked to Leukemia. Besides the carcinogenic effects of cigarette smoking,
increased risks of cardiovascular diseases (including stroke), sudden death,
cardiac arrest, peripheral vascular disease and aortic aneurysm are many serious
diseases related to smoking. Irritation of the lining of the respiratory system
is due to some components known as Ciliotoxic present in cigarette mainstream
smoke and it results in increased bronchial mucus secretion and chronic
decreases in pulmonary and mucociliary function. It is also found that a
carcinogen named reactive oxygen species (ROS) cause inhibition of sodium
potassium pump of the cell and disrupt the function of cell In July 1957,
smoking was recognized as a cause of lung cancer and it is realized that
Environmental Tobacco Smoke (ETS) which is latest aspect of cigarette smoking is
the causative factor of increased risk of lung cancer amongst exposed
non-smokers. Young infants are more susceptible to increased toxicity of
Environmental Tobacco Smoke. According to a report, exposure to secondhand smoke
makes a way to the development of asthma in children. It is also revealed that
in prematurity, the cigarette smoke affects adversely to the human airway of
developing fetus. They are more susceptible to asthma as childhood respiratory
disease . Environmental tobacco smoke, the mixture of about 4000 chemicals poses
risk to infants due to indoor smoking . Apart from second hand smoke or ETS,
there is also a third hand smoke that remains in the dust of smoker’s home for
about two months if the smoker has gone from that place and it will affect the
new coming residents .The results of a study show that the nicotine in the
tobacco smoke get adhere to the indoor surfaces and form carcinogen tobacco
compounds that are dangerous to infants .
Literature provides the link between the maternal smoking and exposure to ETS to
reduced lung growth and increased risks of respiratory infections and childhood
asthma. The severity of these diseases increases with the increase in exposure.
A large number of other problems are also associated with it e.g., Sudden infant
death syndrome, neurocognitive decrements, behavioral problems and greater rates
of adolescent smoking .
The reactive oxygen species formed due to smoking damage the osteoblasts of the
body and causes bones to become weak. After the inhalation of cigarette smoke,
the nicotine present in the smoke reaches to the brain within 10 seconds. Some
individuals are addicted to alcohol, the chronic consumption of alcohol in these
individuals induced brain damages. If the same person is also used to smoking,
the effect of alcohol induced brain damage goes on intensifying, specially
targeting the frontal lobe of brain which is responsible for many body
activities. Nuerocognition is adversely affected by the alcohol addiction
compounded by smoking addiction.
In US smoking is the single leading cause of approximately 400,000 deaths. A
research conducted on smokers and non-smokers to evaluate the potential of
toxicity has shown that teenage addiction to smoking reduces the brain function
by interfering with the development of brain in adolescence. Mostly adults start
smoking between the age of 14 to 18 years and at the age of 18, they completely
become addicted to this habit and it reduces their attention abilities by
affecting prefrontal cortex of brain which in developing stage in adolescence.
In the world, there are about 1.3 billion smokers and deaths due to tobacco use
are estimated to be 5 million persons per year. If the present trend of
consumption will continue, the number of deaths because of smoking will become
nearly double, approximately 10 million at the end of 2020 .It is worthy to say
that not only the smoke, you inhale during smoking but the exposure to the smoke
while standing near a smoker, alone is sufficient to cause harm. Carbon monoxide
that is present in cigarette smoke binds to the hemoglobin and reduces the
oxygen supply to the blood. Carcinogens of tobacco smoke destroy the genes and
causes abnormal growth of cells. Results of many in vivo and in vitro tests show
that the toxicity of cigarettes varies according to the chemical compounds
present in different cigarette of different brands .Different socioeconomic
status and many household policies among people have effect on their children in
term of exposure to smoking . Research has shown that many tobacco companies are
now trying to produce harmless tobacco products. They claim that these products
have reduced exposure to smokers. In other words risk to health may be lessening
by using light cigarette but there is very little knowledge about them. To save
public health from potential toxicity of cigarette smoking is much in debates
now days, the only need is to realize the necessity of testing and examining the
possible harms to the human health before a product came to the market .
It is known that the single largest cause of cancer in the world is smoking. One
out of five cancer deaths are owing to cigarette consumption. 25-40% of smokers
die because of smoking in their middle ages. More deaths bring about due to
smoking than from other diseases. (Cancer research UK, 2009). As a result of
these facts, scientists have been trying to create safer cigarettes than they
are currently present. An important part of blood system, Hemoglobin along with
activated carbon is made known to lower the 90 percent of free-radicals present
in smoke, but this is expensive and therefore is not efficiently coming to the
market (Science news, 2012). An alternative cigarette is an “eclipse cigarette”
that burns itself instead of burning tobacco. Experiments have shown that the
toxicity of eclipse is relatively less as compared to conventional cigarettes
(Foy, et al., 2004). Having a garlic rich diet or other supplementary foods
might be an evidence to strengthen the bone matter or curing the bone fractures
in smokers (Ehnerta, et al., 2012). Many countries are investing in tobacco
control programs. By increasing tobacco prices and by offering affordable
cessation treatments, the best results can be obtained. Smoking should be ban in
public places and media can also play its role to aware the people about the
consequences of smoking (Surgeon General Report, 2010). Despite of all these
efforts, the only way to reduce the toxicity of cigarette smoking is to quit the
smoking and to reduce the exposure to cigarette smoke to avoid the damages due
to second hand smoke.