Acetylcholine (ACh) is an organic chemical that functions in the brain and body of many types of animals (including humans) as a neurotransmitter—a chemical message released by nerve cells to send signals to other cells, such as neurons, muscle cells and gland cells. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Parts in the body that use or are affected by acetylcholine are referred to as cholinergic. Substances that increase or decrease the overall activity of the cholinergic system are called cholinergics and anticholinergics, respectively.
Acetylcholine is the neurotransmitter used at the neuromuscular junction—in other words, it is the chemical that motor neurons
of the nervous system release in order to activate muscles. This
property means that drugs that affect cholinergic systems can have very
dangerous effects ranging from paralysis to convulsions. Acetylcholine
is also a neurotransmitter in the autonomic nervous system, both as an internal transmitter for the sympathetic nervous system and as the final product released by the parasympathetic nervous system. Acetylcholine is the primary neurotransmitter of the parasympathetic nervous system.
In the brain, acetylcholine functions as a neurotransmitter and as a neuromodulator.
The brain contains a number of cholinergic areas, each with distinct
functions; such as playing an important role in arousal, attention,
memory and motivation.
Acetylcholine has also been traced in cells of non-neural origins
and microbes. Recently, enzymes related to its synthesis, degradation
and cellular uptake have been traced back to early origins of
unicellular eukaryotes. The protist pathogen Acanthamoeba
spp. has shown the presence of ACh, which provides growth and
proliferative signals via a membrane located M1-muscarinic receptor
homolog.
Partly because of its muscle-activating function, but also
because of its functions in the autonomic nervous system and brain, many
important drugs exert their effects by altering cholinergic
transmission. Numerous venoms and toxins produced by plants, animals,
and bacteria, as well as chemical nerve agents such as Sarin,
cause harm by inactivating or hyperactivating muscles through their
influences on the neuromuscular junction. Drugs that act on muscarinic acetylcholine receptors, such as atropine,
can be poisonous in large quantities, but in smaller doses they are
commonly used to treat certain heart conditions and eye problems. Scopolamine, which acts mainly on muscarinic receptors in the brain, can cause delirium and amnesia. The addictive qualities of nicotine are derived from its effects on nicotinic acetylcholine receptors in the brain.
Chemistry
Acetylcholine is a choline molecule that has been acetylated at the oxygen atom. Because of the presence of a highly polar, charged ammonium
group, acetylcholine does not penetrate lipid membranes. Because of
this, when the molecule is introduced externally, it remains in the
extracellular space and does not pass through the blood–brain barrier.
Biochemistry
Acetylcholine is synthesized in certain neurons by the enzymecholine acetyltransferase from the compounds choline and acetyl-CoA.
Cholinergic neurons are capable of producing ACh. An example of a
central cholinergic area is the nucleus basalis of Meynert in the basal
forebrain.
The enzyme acetylcholinesterase converts acetylcholine into the inactive metabolitescholine and acetate.
This enzyme is abundant in the synaptic cleft, and its role in rapidly
clearing free acetylcholine from the synapse is essential for proper
muscle function. Certain neurotoxins work by inhibiting acetylcholinesterase, thus leading to excess acetylcholine at the neuromuscular junction, causing paralysis of the muscles needed for breathing and stopping the beating of the heart.
Acetylcholine processing in a synapse. After release acetylcholine is broken down by the enzyme acetylcholinesterase.
Like many other biologically active substances, acetylcholine exerts its effects by binding to and activating receptors located on the surface of cells. There are two main classes of acetylcholine receptor, nicotinic and muscarinic. They are named for chemicals that can selectively activate each type of receptor without activating the other: muscarine is a compound found in the mushroom Amanita muscaria; nicotine is found in tobacco.
Nicotinic acetylcholine receptors are ligand-gated ion channels permeable to sodium, potassium, and calcium
ions. In other words, they are ion channels embedded in cell membranes,
capable of switching from a closed to an open state when acetylcholine
binds to them; in the open state they allow ions to pass through.
Nicotinic receptors come in two main types, known as muscle-type and
neuronal-type. The muscle-type can be selectively blocked by curare, the neuronal-type by hexamethonium.
The main location of muscle-type receptors is on muscle cells, as
described in more detail below. Neuronal-type receptors are located in
autonomic ganglia (both sympathetic and parasympathetic), and in the
central nervous system.
Muscarinic acetylcholine receptors
have a more complex mechanism, and affect target cells over a longer
time frame. In mammals, five subtypes of muscarinic receptors have been
identified, labeled M1 through M5. All of them function as G protein-coupled receptors, meaning that they exert their effects via a second messenger system. The M1, M3, and M5 subtypes are Gq-coupled; they increase intracellular levels of IP3 and calcium by activating phospholipase C. Their effect on target cells is usually excitatory. The M2 and M4 subtypes are Gi/Go-coupled; they decrease intracellular levels of cAMP by inhibiting adenylate cyclase.
Their effect on target cells is usually inhibitory. Muscarinic
acetylcholine receptors are found in both the central nervous system and
the peripheral nervous system of the heart, lungs, upper
gastrointestinal tract, and sweat glands.
Neuromuscular junction
Muscles
contract when they receive signals from motor neurons. The
neuromuscular junction is the site of the signal exchange. The steps of
this process in vertebrates occur as follows: (1) The action potential
reaches the axon terminal. (2) Calcium ions flow into the axon terminal.
(3) Acetylcholine is released into the synaptic cleft.
(4) Acetylcholine binds to postsynaptic receptors. (5) This binding
causes ion channels to open and allows sodium ions to flow into the
muscle cell. (6) The flow of sodium ions across the membrane into the
muscle cell generates an action potential which induces muscle
contraction. Labels: A: Motor neuron axon B: Axon terminal C: Synaptic
cleft D: Muscle cell E: Part of a Myofibril
Acetylcholine is the substance the nervous system uses to activate skeletal muscles, a kind of striated muscle. These are the muscles used for all types of voluntary movement, in contrast to smooth muscle tissue,
which is involved in a range of involuntary activities such as movement
of food through the gastrointestinal tract and constriction of blood
vessels. Skeletal muscles are directly controlled by motor neurons located in the spinal cord or, in a few cases, the brainstem. These motor neurons send their axons through motor nerves, from which they emerge to connect to muscle fibers at a special type of synapse called the neuromuscular junction.
When a motor neuron generates an action potential,
it travels rapidly along the nerve until it reaches the neuromuscular
junction, where it initiates an electrochemical process that causes
acetylcholine to be released into the space between the presynaptic
terminal and the muscle fiber. The acetylcholine molecules then bind to
nicotinic ion-channel receptors on the muscle cell membrane, causing the
ion channels to open. Sodium ions then flow into the muscle cell,
initiating a sequence of steps that finally produce muscle contraction.
Factors that decrease release of acetylcholine (and thereby affecting P-type calcium channels):
The autonomic nervous system controls a wide range of involuntary and unconscious body functions. Its main branches are the sympathetic nervous system and parasympathetic nervous system.
Broadly speaking, the function of the sympathetic nervous system is to
mobilize the body for action; the phrase often invoked to describe it is
fight-or-flight.
The function of the parasympathetic nervous system is to put the body
in a state conducive to rest, regeneration, digestion, and reproduction;
the phrase often invoked to describe it is "rest and digest" or "feed
and breed". Both of these aforementioned systems use acetylcholine, but
in different ways.
At a schematic level, the sympathetic and parasympathetic nervous
systems are both organized in essentially the same way: preganglionic
neurons in the central nervous system send projections to neurons
located in autonomic ganglia, which send output projections to virtually
every tissue of the body. In both branches the internal connections,
the projections from the central nervous system to the autonomic
ganglia, use acetylcholine as a neurotransmitter to innervate (or
excite) ganglia neurons. In the parasympathetic nervous system the
output connections, the projections from ganglion neurons to tissues
that don't belong to the nervous system, also release acetylcholine but
act on muscarinic receptors. In the sympathetic nervous system the
output connections mainly release noradrenaline, although acetylcholine is released at a few points, such as the sudomotor innervation of the sweat glands.
In the central nervous system, ACh has a variety of effects on plasticity, arousal and reward. ACh has an important role in the enhancement of alertness when we wake up, in sustaining attention and in learning and memory.
Damage to the cholinergic (acetylcholine-producing) system in the
brain has been shown to be associated with the memory deficits
associated with Alzheimer's disease. ACh has also been shown to promote REM sleep.
In addition, ACh acts as an important internal transmitter in the striatum, which is part of the basal ganglia. It is released by cholinergic interneurons.
In humans, non-human primates and rodents, these interneurons respond
to salient environmental stimuli with responses that are temporally
aligned with the responses of dopaminergic neurons of the substantia nigra.
Memory
Acetylcholine has been implicated in learning and memory in several ways. The anticholinergic drug, scopolamine, impairs acquisition of new information in humans and animals. In animals, disruption of the supply of acetylcholine to the neocortex impairs the learning of simple discrimination tasks, comparable to the acquisition of factual information and disruption of the supply of acetylcholine to the hippocampus and adjacent cortical areas produces forgetfulness, comparable to anterograde amnesia in humans.
Diseases and disorders
Myasthenia gravis
The disease myasthenia gravis, characterized by muscle weakness and fatigue, occurs when the body inappropriately produces antibodies
against acetylcholine nicotinic receptors, and thus inhibits proper
acetylcholine signal transmission. Over time, the motor end plate is
destroyed. Drugs that competitively inhibit acetylcholinesterase (e.g.,
neostigmine, physostigmine, or primarily pyridostigmine) are effective
in treating this disorder. They allow endogenously released
acetylcholine more time to interact with its respective receptor before
being inactivated by acetylcholinesterase in the synaptic cleft (the
space between nerve and muscle).
Pharmacology
Blocking,
hindering or mimicking the action of acetylcholine has many uses in
medicine. Drugs acting on the acetylcholine system are either agonists
to the receptors, stimulating the system, or antagonists, inhibiting it.
Acetylcholine receptor agonists and antagonists can either have an
effect directly on the receptors or exert their effects indirectly,
e.g., by affecting the enzyme acetylcholinesterase, which degrades the receptor ligand. Agonists increase the level of receptor activation, antagonists reduce it.
Acetylcholine itself does not have therapeutic value as a drug
for intravenous administration because of its multi-faceted action
(non-selective) and rapid inactivation by cholinesterase. However, it is
used in the form of eye drops to cause constriction of the pupil during
cataract surgery, which facilitates quick post-operational recovery.
Nicotinic receptors
Nicotine binds to and activates nicotinic acetylcholine receptors, mimicking the effect of acetylcholine at these receptors. When ACh interacts with a nicotinic ACh receptor, it opens a Na+ channel and Na+
ions flow into the membrane. This causes a depolarization, and results
in an excitatory post-synaptic potential. Thus, ACh is excitatory on
skeletal muscle; the electrical response is fast and short-lived. Curares are arrow poisons, which act at nicotinic receptors and have been used to develop clinically useful therapies.
Muscarinic receptors
Atropine is a non-selective competitive antagonist with Acetylcholine at muscarinic receptors.
Cholinesterase inhibitors
Many ACh receptor agonists work indirectly by inhibiting the enzyme acetylcholinesterase.
The resulting accumulation of acetylcholine causes continuous
stimulation of the muscles, glands, and central nervous system, which
can result in fatal convulsions if the dose is high.
They are examples of enzyme inhibitors, and increase the action of acetylcholine by delaying its degradation; some have been used as nerve agents (Sarin and VX nerve gas) or pesticides (organophosphates and the carbamates).
Many toxins and venoms produced by plants and animals also contain
cholinesterase inhibitors. In clinical use, they are administered in low
doses to reverse the action of muscle relaxants, to treat myasthenia gravis, and to treat symptoms of Alzheimer's disease (rivastigmine, which increases cholinergic activity in the brain).
Synthesis inhibitors
Organic mercurial compounds, such as methylmercury, have a high affinity for sulfhydryl groups,
which causes dysfunction of the enzyme choline acetyltransferase. This
inhibition may lead to acetylcholine deficiency, and can have
consequences on motor function.
Release inhibitors
Botulinum toxin (Botox) acts by suppressing the release of acetylcholine, whereas the venom from a black widow spider (alpha-latrotoxin) has the reverse effect. ACh inhibition causes paralysis. When bitten by a black widow spider, one experiences the wastage of ACh supplies and the muscles begin to contract. If and when the supply is depleted, paralysis occurs.
Comparative biology and evolution
Acetylcholine
is used by organisms in all domains of life for a variety of purposes.
It is believed that choline, a precursor to acetylcholine, was used by
single celled organisms billions of years ago for synthesizing cell membrane phospholipids.
Following the evolution of choline transporters, the abundance of
intracellular choline paved the way for choline to become incorporated
into other synthetic pathways, including acetylcholine production.
Acetylcholine is used by bacteria, fungi, and a variety of other
animals. Many of the uses of acetylcholine rely on its action on ion
channels via GPCRs like membrane proteins.
The two major types of acetylcholine receptors, muscarinic and
nicotinic receptors, have convergently evolved to be responsive to
acetylcholine. This means that rather than having evolved from a common
homolog, these receptors evolved from separate receptor families. It is
estimated that the nicotinic receptor family dates back longer than 2.5
billion years.
Likewise, muscarinic receptors are thought to have diverged from other
GPCRs at least 0.5 billion years ago. Both of these receptor groups have
evolved numerous subtypes with unique ligand affinities and signaling
mechanisms. The diversity of the receptor types enables acetylcholine to
create varying responses depending on which receptor types are
activated, and allow for acetylcholine to dynamically regulate
physiological processes.
History
In 1867, Adolf von Baeyer resolved the structures of choline and acetylcholine and synthetized them both, referring to the latter as "acetylneurin" in the study. Choline is a precursor for acetylcholine. This is why Frederick Walker Mott and William Dobinson Halliburton noted in 1899 that choline injections decreased the blood pressure of animals. Acetylcholine was first noted to be biologically active in 1906, when Reid Hunt (1870–1948) and René de M. Taveau found that it decreased blood pressure in exceptionally tiny doses.
In 1914, Arthur J. Ewins was the first to extract acetylcholine from nature. He identified it as the blood pressure decreasing contaminant from some Claviceps purpureaergot extracts, by the request of Henry Hallett Dale.
Later in 1914, Dale outlined the effects of acetylcholine at various
types of peripheral synapses and also noted that it lowered the blood
pressure of cats via subcutaneous injections even at doses of one nanogram.
The concept neurotransmitters was unknown before 1921, when Otto Loewi noted that the vagus nerve secreted a substance that inhibited the heart muscle whilst working as a professor in the University of Graz. He named it vagusstoff ("vagus substance"), noted it to be a structural analog of choline and suspected it to be acetylcholine.
In 1926, Loewi and E. Navratil deduced that the compound is probably
acetylcholine, as vagusstoff and synthetic acetylcholine lost their
activity in a similar manner when in contact with tissue lysates that contained acetylcholine-degrading enzymes (now known to be cholinesterases). This conclusion was accepted widely. Later studies confirmed the function of acetylcholine as a neurotransmitter.
Universal healthcare (also called universal health coverage, universal coverage, or universal care) is a health care
system in which all residents of a particular country or region are
assured access to health care. It is generally organized around
providing either all residents or only those who cannot afford on their
own, with either health services or the means to acquire them, with the
end goal of improving health outcomes.
Universal healthcare does not imply coverage for all cases and
for all people – only that all people have access to healthcare. Some
universal healthcare systems are government-funded, while others are
based on a requirement that all citizens purchase private health
insurance. Universal healthcare can be determined by three critical
dimensions: who is covered, what services are covered, and how much of
the cost is covered. It is described by the World Health Organization as a situation where citizens can access health services without incurring financial hardship.
The Director General of WHO describes universal health coverage as the
“single most powerful concept that public health has to offer” since it
unifies “services and delivers them in a comprehensive and integrated
way”.
One of the goals with universal healthcare is to create a system of
protection which provides equality of opportunity for people to enjoy
the highest possible level of health.
The first move towards a national health insurance system was launched in Germany
in 1883, with the Sickness Insurance Law. Industrial employers were
mandated to provide injury and illness insurance for their low-wage
workers, and the system was funded and administered by employees and
employers through "sick funds", which were drawn from deductions in
workers' wages and from employers' contributions. Named after Prussian
Chancellor Otto von Bismarck, this social health insurance model was the
first form of universal care in modern times. Other countries soon began to follow suit. In the United Kingdom, the National Insurance Act 1911
provided coverage for primary care (but not specialist or hospital
care) for wage earners, covering about one-third of the population. The Russian Empire
established a similar system in 1912, and other industrialized
countries began following suit. By the 1930s, similar systems existed in
virtually all of Western and Central Europe. Japan introduced an employee health insurance law in 1927, expanding further upon it in 1935 and 1940. Following the Russian Revolution of 1917, the Soviet Union established a fully public and centralized health care system in 1920. However, it was not a truly universal system at that point, as rural residents were not covered.
In New Zealand, a universal health care system was created in a series of steps, from 1939 to 1941. In Australia, the state of Queensland introduced a free public hospital system in 1946.
Following World War II, universal health care systems began to be set up around the world. On July 5, 1948, the United Kingdom launched its universal National Health Service. Universal health care was next introduced in the Nordic countries of Sweden (1955), Iceland (1956), Norway (1956), Denmark (1961), and Finland (1964). Universal health insurance was introduced in Japan in 1961, and in Canada through stages, starting with the province of Saskatchewan in 1962, followed by the rest of Canada from 1968 to 1972. A public healthcare system was introduced in Egypt following the Egyptian revolution of 1952. Centralized public healthcare systems were set up in the Eastern bloc countries. The Soviet Union extended universal health care to its rural residents in 1969. Kuwait and Bahrain introduced their universal healthcare systems in 1950 and 1957 respectively (prior to independence). Italy introduced its Servizio Sanitario Nazionale (National Health Service) in 1978. Universal health insurance was implemented in Australia in 1975 with the Medibank, which led to universal coverage under the current Medicare system from 1984.
From the 1970s to the 2000s, Southern and Western European
countries began introducing universal coverage, most of them building
upon previous health insurance programs to cover the whole population.
For example, France
built upon its 1928 national health insurance system, with subsequent
legislation covering a larger and larger percentage of the population,
until the remaining 1% of the population that was uninsured received
coverage in 2000. Single payer healthcare systems were introduced in Finland (1972), Portugal (1979), Cyprus (1980), and Spain (1986), and Iceland (1990). Switzerland introduced a universal healthcare system based on an insurance mandate in 1994. In addition, universal health coverage was introduced in some Asian countries, including South Korea (1989), Taiwan (1995), Singapore (1993), Israel (1995), and Thailand (2001).
Following the collapse of the Soviet Union, Russia retained and reformed its universal health care system, as did other now-independent former Soviet republics and Eastern bloc countries.
Beyond the 1990s, many countries in Latin America, the Caribbean, Africa, and the Asia-Pacific region, including developing countries, took steps to bring their populations under universal health coverage, including China which has the largest universal health care system in the world and Brazil's SUS which improved coverage up to 80% of the population. India introduced a tax-payer funded decentralised universal healthcare system that helped reduce mortality rates and malnutrition. A 2012 study examined progress being made by these countries, focusing on nine in particular: Ghana, Rwanda, Nigeria, Mali, Kenya, Indonesia, the Philippines, and Vietnam.
Currently, most industrialized countries and many developing
countries operate some form of publicly funded health care with
universal coverage as the goal. According to the National Academy of Medicine and others, the United States is the only wealthy, industrialized nation that does not provide universal health care.
Funding models
Universal health care in most countries has been achieved by a mixed model of funding. General taxation
revenue is the primary source of funding, but in many countries it is
supplemented by specific charge (which may be charged to the individual
or an employer) or with the option of private payments (by direct or
optional insurance) for services beyond those covered by the public
system. Almost all European systems are financed through a mix of public
and private contributions. Most universal health care systems are funded primarily by tax revenue (as in Portugal,India, Spain, Denmark and Sweden). Some nations, such as Germany, France, and Japan,
employ a multi-payer system in which health care is funded by private
and public contributions. However, much of the non-government funding
comes from contributions from employers and employees to regulated non-profit
sickness funds. Contributions are compulsory and defined according to
law. A distinction is also made between municipal and national
healthcare funding. For example, one model is that the bulk of the
healthcare is funded by the municipality, specialty healthcare is
provided and possibly funded by a larger entity, such as a municipal
co-operation board or the state, and medications are paid for by a state
agency. A paper by Sherry A. Glied from Columbia University
found that universal health care systems are modestly redistributive
and that the progressivity of health care financing has limited
implications for overall income inequality.
Compulsory insurance
This is usually enforced via legislation requiring residents to
purchase insurance, but sometimes the government provides the insurance.
Sometimes there may be a choice of multiple public and private funds
providing a standard service (as in Germany) or sometimes just a single
public fund (as in the Canadian provinces). Healthcare in Switzerland is based on compulsory insurance.
In some European countries where private insurance and universal
health care coexist, such as Germany, Belgium and the Netherlands, the
problem of adverse selection
is overcome by using a risk compensation pool to equalize, as far as
possible, the risks between funds. Thus, a fund with a predominantly
healthy, younger population has to pay into a compensation pool and a
fund with an older and predominantly less healthy population would
receive funds from the pool. In this way, sickness funds compete on
price and there is no advantage in eliminating people with higher risks
because they are compensated for by means of risk-adjusted capitation
payments. Funds are not allowed to pick and choose their policyholders
or deny coverage, but they compete mainly on price and service. In some
countries, the basic coverage level is set by the government and cannot
be modified.
The Republic of Ireland at one time had a "community rating" system by VHI,
effectively a single-payer or common risk pool. The government later
opened VHI to competition, but without a compensation pool. That
resulted in foreign insurance companies entering the Irish market and
offering much less expensive health insurance to relatively healthy
segments of the market, which then made higher profits at VHI's expense.
The government later reintroduced community rating by a pooling
arrangement and at least one main major insurance company, BUPA,
withdrew from the Irish market.
In Poland, people are obliged to pay a percentage of the average
monthly wage to the state, even if they are covered by private
insurance. People working under a employment contract
pay a percentage of their wage, while entrepreneurs pay a fixed rate,
based on the average national wage. Unemployed people are insured by the
labor office.
Among the potential solutions posited by economists are
single-payer systems as well as other methods of ensuring that health
insurance is universal, such as by requiring all citizens to purchase
insurance or by limiting the ability of insurance companies to deny
insurance to individuals or vary price between individuals.
Single payer
Single-payer health care is a system in which the government, rather than private insurers, pays for all health care costs.
Single-payer systems may contract for healthcare services from private
organizations, or own and employ healthcare resources and personnel (as
was the case in England before the introduction of the Health and Social Care Act). In some instances, such as Italy and Spain, both these realities may exist at the same time.
"Single-payer" thus describes only the funding mechanism and refers to
health care financed by a single public body from a single fund and does
not specify the type of delivery or for whom doctors work. Although the
fund holder is usually the state, some forms of single-payer use a
mixed public-private system.
Tax-based financing
In
tax-based financing, individuals contribute to the provision of health
services through various taxes. These are typically pooled across the
whole population unless local governments raise and retain tax revenues.
Some countries (notably the United Kingdom, Ireland, New Zealand, Italy, Spain, Brazil, Portugal, India and the Nordic countries)
choose to fund public health care directly from taxation alone. Other
countries with insurance-based systems effectively meet the cost of
insuring those unable to insure themselves via social security
arrangements funded from taxation, either by directly paying their
medical bills or by paying for insurance premiums for those affected.
Social health insurance
In
a social health insurance system, contributions from workers, the
self-employed, enterprises and governments are pooled into single or
multiple funds on a compulsory basis. This is based on risk pooling. The social health insurance model is also referred to as the Bismarck Model, after Chancellor Otto von Bismarck, who introduced the first universal health care system in Germany in the 19th century.
The funds typically contract with a mix of public and private providers
for the provision of a specified benefit package. Preventive and public
health care may be provided by these funds or responsibility kept
solely by the Ministry of Health. Within social health insurance, a
number of functions may be executed by parastatal or non-governmental
sickness funds, or in a few cases, by private health insurance
companies. Social health insurance is used in a number of Western
European countries and increasingly in Eastern Europe as well as in
Israel and Japan.
Private insurance
In
private health insurance, premiums are paid directly from employers,
associations, individuals and families to insurance companies, which
pool risks across their membership base. Private insurance includes
policies sold by commercial for-profit firms, non-profit companies and
community health insurers. Generally, private insurance is voluntary in
contrast to social insurance programs, which tend to be compulsory.
In some countries with universal coverage, private insurance
often excludes certain health conditions that are expensive and the
state health care system can provide coverage. For example, in the
United Kingdom, one of the largest private health care providers is BUPA, which has a long list of general exclusions even in its highest coverage policy, most of which are routinely provided by the National Health Service. In the United States, dialysis treatment for end stage renal failure is generally paid for by government and not by the insurance industry. Those with privatized Medicare (Medicare Advantage)
are the exception and must get their dialysis paid for through their
insurance company. However, those with end-stage kidney failure
generally cannot buy Medicare Advantage plans.
In the Netherlands, which has regulated competition for its main
insurance system (but is subject to a budget cap), insurers must cover a
basic package for all enrollees, but may choose which additional
services they offer in supplementary plans; which most people possess.
The Planning Commission of India has also suggested that the country should embrace insurance to achieve universal health coverage. General tax revenue is currently used to meet the essential health requirements of all people.
Community-based health insurance
A
particular form of private health insurance that has often emerged, if
financial risk protection mechanisms have only a limited impact, is
community-based health insurance. Individual members of a specific
community pay to a collective health fund which they can draw from when
they need medical care. Contributions are not risk-related and there is
generally a high level of community involvement in the running of these
plans.
Universal health care systems vary according to the degree of
government involvement in providing care or health insurance. In some
countries, such as Canada, the UK, Spain, Italy, Australia, and the
Nordic countries, the government has a high degree of involvement in the
commissioning or delivery of health care services and access is based
on residence rights, not on the purchase of insurance. Others have a
much more pluralistic delivery system, based on obligatory health with
contributory insurance rates related to salaries or income and usually
funded by employers and beneficiaries jointly.
Sometimes, the health funds are derived from a mixture of
insurance premiums, salary-related mandatory contributions by employees
or employers to regulated sickness funds, and by government taxes. These
insurance based systems tend to reimburse private or public medical
providers, often at heavily regulated rates, through mutual or publicly
owned medical insurers. A few countries, such as the Netherlands and
Switzerland, operate via privately owned but heavily regulated private
insurers, which are not allowed to make a profit from the mandatory
element of insurance but can profit by selling supplemental insurance.
Universal health care is a broad concept that has been
implemented in several ways. The common denominator for all such
programs is some form of government action aimed at extending access to
health care as widely as possible and setting minimum standards. Most
implement universal health care through legislation, regulation, and
taxation. Legislation and regulation direct what care must be provided,
to whom, and on what basis. Usually, some costs are borne by the patient
at the time of consumption, but the bulk of costs come from a
combination of compulsory insurance and tax revenues. Some programs are
paid for entirely out of tax revenues. In others, tax revenues are used
either to fund insurance for the very poor or for those needing
long-term chronic care.
A critical concept in the delivery of universal healthcare is
that of population healthcare. This is a way of organizing the delivery,
and allocating resources, of healthcare (and potentially social care)
based on populations in a given geography with a common need (such as asthma, end of life, urgent care).
Rather than focus on institutions such as hospitals, primary care,
community care etc. the system focuses on the population with a common
as a whole. This includes people currently being treated, and those that
are not being treated but should be (i.e. where there is health inequity). This approach encourages integrated care and a more effective use of resources.
The United Kingdom National Audit Office
in 2003 published an international comparison of ten different health
care systems in ten developed countries, nine universal systems against
one non-universal system (the United States), and their relative costs
and key health outcomes. A wider international comparison of 16 countries, each with universal health care, was published by the World Health Organization in 2004. In some cases, government involvement also includes directly managing the health care system, but many countries use mixed public-private systems to deliver universal health care.
Tobacco smoking is the practice of burning tobacco and ingesting the tobacco smoke that is produced. The smoke may be inhaled, as is done with cigarettes, or simply released from the mouth, as is generally done with pipes and cigars. The practice is believed to have begun as early as 5000–3000 BC in Mesoamerica and South America. Tobacco was introduced to Eurasia in the late 17th century by European colonists, where it followed common trade routes. The practice encountered criticism from its first import into the Western world
onwards but embedded itself in certain strata of a number of societies
before becoming widespread upon the introduction of automated
cigarette-rolling apparatus.
German scientists identified a link between smoking and lung cancer in the late 1920s, leading to the first anti-smoking campaign in modern history, albeit one truncated by the collapse of Nazi Germany at the end of World War II. In 1950, British researchers demonstrated a clear relationship between smoking and cancer.
Evidence continued to mount in the 1980s, which prompted political
action against the practice. Rates of consumption since 1965 in the developed world have either peaked or declined. However, they continue to climb in the developing world.
Smoking is the most common method of consuming tobacco, and
tobacco is the most common substance smoked. The agricultural product is
often mixed with additives and then combusted. The resulting smoke is then inhaled and the active substances absorbed through the alveoli in the lungs or the oral mucosa. Many substances in cigarette smoke trigger chemical reactions in nerve endings, which heighten heart rate, alertness and reaction time, among other things. Dopamine and endorphins are released, which are often associated with pleasure.
As of 2008 to 2010, tobacco is used by about 49% of men and 11% of
women aged 15 or older in fourteen low-income and middle-income
countries (Bangladesh, Brazil, China, Egypt, India, Mexico, Philippines,
Poland, Russia, Thailand, Turkey, Ukraine, Uruguay and Vietnam), with
about 80% of this usage in the form of smoking. The gender gap tends to be less pronounced in lower age groups.
Many smokers begin during adolescence or early adulthood. During the early stages, a combination of perceived pleasure acting as positive reinforcement and desire to respond to social peer pressure
may offset the unpleasant symptoms of initial use, which typically
include nausea and coughing. After an individual has smoked for some
years, the avoidance of withdrawal symptoms and negative reinforcement become the key motivations to continue.
A 2009 study of first smoking experiences of seventh-grade
students found out that the most common factor leading students to
smoke is cigarette advertisements. Smoking by parents, siblings and
friends also encourages students to smoke.
History
Use in ancient cultures
Aztec women are handed flowers and smoking tubes before eating at a banquet, Florentine Codex, 16th century.
Smoking's history dates back to as early as 5000–3000 BC, when the agricultural product began to be cultivated in Mesoamerica and South America;
consumption later evolved into burning the plant substance either by
accident or with intent of exploring other means of consumption. The practice worked its way into shamanistic rituals. Many ancient civilizations – such as the Babylonians,
the Indians, and the Chinese – burnt incense during religious rituals.
Smoking in the Americas probably had its origins in the incense-burning
ceremonies of shamans but was later adopted for pleasure or as a social tool.
The smoking of tobacco and various hallucinogenic drugs was used to
achieve trances and to come into contact with the spirit world. Also, to stimulate respiration, tobacco smoke enemas were used.
Eastern North American tribes would carry large amounts of
tobacco in pouches as a readily accepted trade item and would often
smoke it in ceremonial pipes, either in sacred ceremonies or to seal bargains. Adults as well as children enjoyed the practice.
It was believed that tobacco was a gift from the Creator and that the
exhaled tobacco smoke was capable of carrying one's thoughts and prayers
to heaven.
Apart from smoking, tobacco had a number of uses as medicine. As a
pain killer it was used for earache and toothache and occasionally as a
poultice.
Smoking was said by the desert Indians to be a cure for colds,
especially if the tobacco was mixed with the leaves of the small Desert sage, Salvia dorrii, or the root of Indian balsam or cough root, Leptotaenia multifida, the addition of which was thought to be particularly good for asthma and tuberculosis.
Popularization
Gentlemen Smoking and Playing Backgammon in an Interior by Dirck Hals, 1627
In 1612, six years after the settlement of Jamestown, Virginia, John Rolfe
was credited as the first settler to successfully raise tobacco as a
cash crop. The demand quickly grew as tobacco, referred to as "brown
gold", revived the Virginia joint stock company from its failed gold expeditions.
In order to meet demands from the Old World, tobacco was grown in
succession, quickly depleting the soil. This became a motivator to
settle west into the unknown continent, and likewise an expansion of
tobacco production. Indentured servitude became the primary labor force up until Bacon's Rebellion, from which the focus turned to slavery. This trend abated following the American Revolution as slavery became regarded as unprofitable. However, the practice was revived in 1794 with the invention of the cotton gin.
Frenchman Jean Nicot
(from whose name the word nicotine is derived) introduced tobacco to
France in 1560, and tobacco then spread to England. The first report of a
smoking Englishman is of a sailor in Bristol in 1556, seen "emitting
smoke from his nostrils". Like tea, coffee and opium, tobacco was just one of many intoxicants that was originally used as a form of medicine. Tobacco was introduced around 1600 by French merchants in what today is modern-day Gambia and Senegal. At the same time, caravans from Morocco brought tobacco to the areas around Timbuktu,
and the Portuguese brought the commodity (and the plant) to southern
Africa, establishing the popularity of tobacco throughout all of Africa
by the 1650s.
Soon after its introduction to the Old World, tobacco came under frequent criticism from state and religious leaders. James VI and I, King of Scotland and England, produced the treatise A Counterblaste to Tobacco in 1604, and also introduced excise duty on the product. Murad IV, sultan of the Ottoman Empire 1623–40 was among the first to attempt a smoking ban by claiming it was a threat to public morals and health. The Chongzhen Emperor of China issued an edict banning smoking two years before his death and the overthrow of the Ming dynasty. Later, the Manchu rulers of the Qing dynasty, would proclaim smoking "a more heinous crime than that even of neglecting archery". In Edo period Japan, some of the earliest tobacco plantations were scorned by the shogunate
as being a threat to the military economy by letting valuable farmland
go to waste for the use of a recreational drug instead of being used to
plant food crops.
Bonsack's cigarette rolling machine, as shown on U.S. patent 238,640
Religious leaders have often been prominent among those who considered smoking immoral or outright blasphemous. In 1634, the Patriarch of Moscow
forbade the sale of tobacco, and sentenced men and women who flouted
the ban to have their nostrils slit and their backs flayed. Pope Urban VIII
likewise condemned smoking on holy places in a papal bull of 1624.
Despite some concerted efforts, restrictions and bans were largely
ignored. When James I of England, a staunch anti-smoker and the author of A Counterblaste to Tobacco,
tried to curb the new trend by enforcing a 4000% tax increase on
tobacco in 1604 it was unsuccessful, as suggested by the presence of
around 7,000 tobacco outlets in London by the early 17th century. From
this point on for some centuries, several administrations withdrew from
efforts at discouragement and instead turned tobacco trade and
cultivation into sometimes lucrative government monopolies.
By the mid-17th century most major civilizations had been
introduced to tobacco smoking and in many cases had already assimilated
it into the native culture, despite some continued attempts upon the
parts of rulers to eliminate the practice with penalties or fines.
Tobacco, both product and plant, followed the major trade routes to
major ports and markets, and then on into the hinterlands. The English
language term smoking appears to have entered currency in the late 18th century, before which less abbreviated descriptions of the practice such as drinking smoke were also in use.
Growth in the US remained stable until the American Civil War in 1860s, when the primary agricultural workforce shifted from slavery to sharecropping. This, along with a change in demand, accompanied the industrialization of cigarette production as craftsman James Bonsack created a machine in 1881 to partially automate their manufacture.
In Germany, anti-smoking groups, often associated with anti-liquor groups, first published advocacy against the consumption of tobacco in the journal Der Tabakgegner (The Tobacco Opponent) in 1912 and 1932. In 1929, Fritz Lickint
of Dresden, Germany, published a paper containing formal statistical
evidence of a lung cancer–tobacco link. During the Great Depression Adolf Hitler condemned his earlier smoking habit as a waste of money,
and later with stronger assertions. This movement was further
strengthened with Nazi reproductive policy as women who smoked were
viewed as unsuitable to be wives and mothers in a German family. In the 20th century, smoking was common. There were social events like the smoke night which promoted the habit.
The anti-tobacco movement in Nazi Germany
did not reach across enemy lines during the Second World War, as
anti-smoking groups quickly lost popular support. By the end of the
Second World War, American cigarette manufacturers quickly reentered the
German black market. Illegal smuggling of tobacco became prevalent, and leaders of the Nazi anti-smoking campaign were silenced. As part of the Marshall Plan, the United States shipped free tobacco to Germany; with 24,000 tons in 1948 and 69,000 tons in 1949. Per capita yearly cigarette consumption in post-war Germany steadily rose from 460 in 1950 to 1,523 in 1963.
By the end of the 20th century, anti-smoking campaigns in Germany were
unable to exceed the effectiveness of the Nazi-era climax in the years
1939–41 and German tobacco health research was described by Robert N. Proctor as "muted".
A
lengthy study conducted in order to establish the strong association
necessary for legislative action (US cigarette consumption per person
blue, male lung cancer rate green)
In 1954, the British Doctors Study,
a prospective study of some 40 thousand doctors for about 2.5 years,
confirmed the suggestion, based on which the government issued advice
that smoking and lung cancer rates were related. In January 1964, the United States Surgeon General's Report on Smoking and Health likewise began suggesting the relationship between smoking and cancer.
As scientific evidence mounted in the 1980s, tobacco companies claimed contributory negligence
as the adverse health effects were previously unknown or lacked
substantial credibility. Health authorities sided with these claims up
until 1998, from which they reversed their position. The Tobacco Master Settlement Agreement,
originally between the four largest US tobacco companies and the
Attorneys General of 46 states, restricted certain types of tobacco
advertisement and required payments for health compensation; which later
amounted to the largest civil settlement in United States history.
Social campaigns have been instituted in many places to discourage smoking, such as Canada's National Non-Smoking Week.
From 1965 to 2006, rates of smoking in the United States declined from 42% to 20.8%.
The majority of those who quit were professional, affluent men.
Although the per-capita number of smokers decreased, the average number
of cigarettes consumed per person per day increased from 22 in 1954 to
30 in 1978. This paradoxical event suggests that those who quit smoked
less, while those who continued to smoke moved to smoke more light
cigarettes. The trend has been paralleled by many industrialized nations as rates have either leveled-off or declined. In the developing world, however, tobacco consumption continues to rise at 3.4% in 2002.
In Africa, smoking is in most areas considered to be modern, and many
of the strong adverse opinions that prevail in the West receive much
less attention. Today Russia leads as the top consumer of tobacco followed by Indonesia, Laos, Ukraine, Belarus, Greece, Jordan, and China.
As a result of public pressure and the FDA, Walmart and Sam's
club announced that they were raising the minimum age to purchase
tobacco products, including all e-cigarettes, to 21 starting 1 July
2019.
Consumption
Methods
Tobacco is an agricultural product processed from the fresh leaves of plants in the genus Nicotiana. The genus contains a number of species, however, Nicotiana tabacum is the most commonly grown. Nicotiana rustica follows as second containing higher concentrations of nicotine. These leaves are harvested and cured to allow for the slow oxidation and degradation of carotenoids
in tobacco leaf. This produces certain compounds in the tobacco leaves
which can be attributed to sweet hay, tea, rose oil, or fruity aromatic
flavors. Before packaging, the tobacco is often combined with other
additives in order to enhance the addictive potency, shift the products pH, or improve the effects of smoke by making it more palatable. In the United States these additives are regulated to 599 substances. The product is then processed, packaged, and shipped to consumer markets.
Basma leaves curing in the sun at Pomak village of Xanthi, Thrace, Greece.
Processed tobacco pressed into flakes for pipe smoking
Beedi
Beedis
are thin South Asian cigarettes filled with tobacco flakes and wrapped
in a tendu leaf tied with a string at one end. They produce higher
levels of carbon monoxide, nicotine, and tar than cigarettes typical in
the United States.
Tendu Patta (Leaf) collection for Beedi industries
Cigars
Cigars
are tightly rolled bundles of dried and fermented tobacco which are
ignited so that smoke may be drawn into the smoker's mouth. They are
generally not inhaled because of the high alkalinity of the smoke, which
can quickly become irritating to the trachea and lungs. The prevalence
of cigar smoking varies depending on location, historical period, and
population surveyed, and prevalence estimates vary somewhat depending on
the survey method. The United States is the top consuming country by
far, followed by Germany and the United Kingdom; the US and Western
Europe account for about 75% of cigar sales worldwide. As of 2005 it is estimated that 4.3% of men and 0.3% of women smoke cigars in the USA.
Cigarettes
Cigarettes,
French for "small cigar", are a product consumed through smoking and
manufactured out of cured and finely cut tobacco leaves and
reconstituted tobacco, often combined with other additives, which are
then rolled or stuffed into a paper-wrapped cylinder. Cigarettes are ignited and inhaled, usually through a cellulose acetate filter, into the mouth and lungs.
Hookah
Hookah
are a single or multi-stemmed (often glass-based) water pipe for
smoking. Originally from India. The hookah was a symbol of pride and
honor for the landlords, kings and other such high class people. Now,
the hookah has gained immense popularity, especially in the Middle East.
A hookah operates by water filtration and indirect heat. It can be used
for smoking herbal fruits, tobacco, or cannabis.
Kretek
Kretek are cigarettes made with a complex blend of tobacco, cloves
and a flavoring "sauce". It was first introduced in the 1880s in Kudus,
Java, to deliver the medicinal eugenol of cloves to the lungs. The
quality and variety of tobacco play an important role in kretek
production, from which kretek can contain more than 30 types of tobacco.
Minced dried clove buds weighing about one-third of the tobacco blend
are added to add flavoring. In 2004 the United States prohibited
cigarettes from having a "characterizing flavor" of certain ingredients
other than tobacco and menthol, thereby removing kretek from being
classified as cigarettes.
Pipe smoking
Pipe smoking
is done with a tobacco pipe, typically consisting of a small chamber
(the bowl) for the combustion of the tobacco to be smoked and a thin
stem (shank) that ends in a mouthpiece (the bit). Shredded pieces of
tobacco are placed into the chamber and ignited.
Roll-your-own
Roll-your-own
or hand-rolled cigarettes, often called "rollies", "cigi" or
"Roll-ups", are very popular particularly in European countries and the
UK. These are prepared from loose tobacco, cigarette papers, and filters
all bought separately. They are usually much cheaper than ready-made
cigarettes and small contraptions can be bought making the process
easier.
Vaporizer
A vaporizer
is a device used to sublimate the active ingredients of plant material.
Rather than burning the herb, which produces potentially irritating,
toxic, or carcinogenic
by-products; a vaporizer heats the material in a partial vacuum so that
the active compounds contained in the plant boil off into a vapor. This
method is often preferable when medically administrating the smoke
substance, as opposed to directly pyrolyzing the plant material.
Physiology
A graph that shows the efficiency of smoking as a way to absorb nicotine compared to other forms of intake.
The active substances in tobacco, especially cigarettes, are
administered by burning the leaves and inhaling the vaporized gas that
results. This quickly and effectively delivers substances into the
bloodstream by absorption through the alveoli in the lungs. The lungs contain some 300 million alveoli, which amounts to a surface area of over 70 m2
(about the size of a tennis court). This method is not completely
efficient as not all of the smoke will be inhaled, and some amount of
the active substances will be lost in the process of combustion, pyrolysis. Pipe and Cigar smoke are not inhaled because of its high alkalinity, which are irritating to the trachea
and lungs. However, because of its higher alkalinity (pH 8.5) compared
to cigarette smoke (pH 5.3), non-ionized nicotine is more readily
absorbed through the mucous membranes in the mouth. Nicotine absorption from cigar and pipe, however, is much less than that from cigarette smoke. Nicotine and cocaine activate similar patterns of neurons, which supports the existence of common substrates among these drugs.
The absorbed nicotine mimics nicotinic acetylcholine which when bound to nicotinic acetylcholine receptors prevents the reuptake of acetylcholine thereby increasing that neurotransmitter in those areas of the body.
These nicotinic acetylcholine receptors are located in the central
nervous system and at the nerve-muscle junction of skeletal muscles;
whose activity increases heart rate, alertness, and faster reaction times.
Nicotine acetylcholine stimulation is not directly addictive. However,
since dopamine-releasing neurons are abundant on nicotine receptors,
dopamine is released; and, in the nucleus accumbens, dopamine is associated with motivation causing reinforcing behavior. Dopamine increase, in the prefrontal cortex, may also increase working memory.
When tobacco is smoked, most of the nicotine is pyrolyzed.
However, a dose sufficient to cause mild somatic dependency and mild to
strong psychological dependency remains. There is also a formation of harmane (an MAO inhibitor) from the acetaldehyde in tobacco smoke. This may play a role in nicotine addiction, by facilitating a dopamine release in the nucleus accumbens as a response to nicotine stimuli.
Using rat studies, withdrawal after repeated exposure to nicotine
results in less responsive nucleus accumbens cells, which produce
dopamine responsible for reinforcement.
Demographics
Percentage of males smoking any tobacco product
Percentage of females smoking any tobacco product. Note that there is a difference between the scales used for males and the scales used for females.
As of 2000, smoking was practiced by around 1.22 billion people. At
current rates of 'smoker replacement' and market growth, this may reach
around 1.9 billion in 2025.
Smoking may be up to five times more prevalent among men than women in some communities, although the gender gap usually declines with younger age. In some developed countries smoking rates for men have peaked and begun to decline, while for women they continue to climb.
As of 2002, about twenty percent of young teenagers (13–15)
smoked worldwide. 80,000 to 100,000 children begin smoking every day,
roughly half of whom live in Asia. Half of those who begin smoking in adolescent years are projected to go on to smoke for 15 to 20 years. As of 2019 in the United States, roughly 800,000 high school students smoke.
The World Health Organization
(WHO) states that "Much of the disease burden and premature mortality
attributable to tobacco use disproportionately affect the poor". Of the
1.22 billion smokers, 1 billion of them live in developing or
transitional economies. Rates of smoking have leveled off or declined in
the developed world. In the developing world, however, tobacco consumption is rising by 3.4% per year as of 2002.
The WHO in 2004 projected 58.8 million deaths to occur globally, from which 5.4 million are tobacco-attributed, and 4.9 million as of 2007. As of 2002, 70% of the deaths are in developing countries. As of 2017, smoking causes one in ten deaths worldwide, with half of those deaths in the US, China, India and Russia.
Most smokers begin smoking during adolescence or early adulthood.
Some studies also show that smoking can also be linked to various mental
health complications.
Smoking has elements of risk-taking and rebellion, which often appeal
to young people. The presence of peers that smoke and media featuring
high-status models smoking may also encourage smoking. Because teenagers
are influenced more by their peers than by adults, attempts by parents,
schools, and health professionals at preventing people from trying
cigarettes are often unsuccessful.
Children of smoking parents are more likely to smoke than
children with non-smoking parents. Children of parents who smoke are
less likely to quit smoking.
One study found that parental smoking cessation was associated with
less adolescent smoking, except when the other parent currently smoked.
A current study tested the relation of adolescent smoking to rules
regulating where adults are allowed to smoke in the home. Results showed
that restrictive home smoking policies were associated with lower
likelihood of trying smoking for both middle and high school students.
Behavioural research generally indicates that teenagers begin
their smoking habits due to peer pressure, and cultural influence
portrayed by friends. However, one study found that direct pressure to
smoke cigarettes played a less significant part in adolescent smoking,
with adolescents also reporting low levels of both normative and direct pressure to smoke cigarettes. Mere exposure to tobacco retailers may motivate smoking behaviour in adults.
A similar study suggested that individuals may play a more active role
in starting to smoke than has previously been thought and that social
processes other than peer pressure also need to be taken into account. Another study's results indicated that peer pressure
was significantly associated with smoking behavior across all age and
gender cohorts, but that intrapersonal factors were significantly more
important to the smoking behavior of 12- to 13-year-old girls than
same-age boys. Within the 14- to 15-year-old age group, one peer
pressure variable emerged as a significantly more important predictor of
girls' than boys' smoking. It is debated whether peer pressure or self-selection is a greater cause of adolescent smoking.
Psychologist Hans Eysenck (who later was questioned for nonplausible results and unsafe publications)) developed a personality profile for the typical smoker. Extraversion
is the trait that is most associated with smoking, and smokers tend to
be sociable, impulsive, risk taking, and excitement seeking individuals.
Persistence
The reasons given by some smokers for this activity have been categorized as addictive smoking, pleasure from smoking, tension reduction/relaxation, social smoking, stimulation, habit/automatism, and handling. There are gender differences in how much each of these reasons contribute, with females more likely than males to cite tension reduction/relaxation, stimulation and social smoking.
Some smokers argue that the depressant effect of smoking allows them to calm their nerves, often allowing for increased concentration. However, according to the Imperial College London,
"Nicotine seems to provide both a stimulant and a depressant effect,
and it is likely that the effect it has at any time is determined by the
mood of the user, the environment and the circumstances of use. Studies
have suggested that low doses have a depressant effect, while higher
doses have stimulant effect."
Patterns
A
number of studies have established that cigarette sales and smoking
follow distinct time-related patterns. For example, cigarette sales in
the United States of America have been shown to follow a strongly
seasonal pattern, with the high months being the months of summer, and
the low months being the winter months.
Similarly, smoking has been shown to follow distinct circadian
patterns during the waking day—with the high point usually occurring
shortly after waking in the morning, and shortly before going to sleep
at night.
Economic
In countries where there is a universally funded healthcare
system, the government covers the cost of medical care for smokers who
become ill through smoking in the form of increased taxes. Two broad
debating positions exist on this front, the "pro-smoking" argument
suggesting that heavy smokers generally do not live long enough to
develop the costly and chronic illnesses which affect the elderly,
reducing society's healthcare burden, and the "anti-smoking" argument
suggests that the healthcare burden is increased because smokers get
chronic illnesses younger and at a higher rate than the general
population. Data on both positions has been contested. The Centers for Disease Control and Prevention published research in 2002 claiming that the cost of each pack of cigarettes sold in the United States was more than $7 in medical care and lost productivity.
The cost may be higher, with another study putting it as high as $41
per pack, most of which however is on the individual and his/her family.
This is how one author of that study puts it when he explains the very
low cost for others: "The reason the number is low is that for private
pensions, Social Security, and Medicare — the biggest factors in
calculating costs to society — smoking actually saves money. Smokers die
at a younger age and don't draw on the funds they've paid into those
systems."
Other research demonstrates that premature death caused by smoking may
redistribute Social Security income in unexpected ways that affect
behavior and reduce the economic well-being of smokers and their
dependents.
To further support this, whatever the rate of smoking consumption is
per day, smokers have a greater lifetime medical cost on average
compared to a non-smoker by an estimated $6000
Between the cost for lost productivity and health care expenditures
combined, cigarette smoking costs at least 193 billion dollars (Research
also shows that smokers earn less money than nonsmokers). As for secondhand smoke, the cost is over 10 billion dollars.
By contrast, some non-scientific studies, including one conducted by Philip Morris in the Czech Republic called Public Finance Balance of Smoking in the Czech Republic and another by the Cato Institute,
support the opposite position. Philip Morris has explicitly apologised
for the former study, saying: "The funding and public release of this
study which, among other things, detailed purported cost savings to the
Czech Republic due to premature deaths of smokers, exhibited terrible
judgment as well as a complete and unacceptable disregard of basic human
values. For one of our tobacco companies to commission this study was
not just a terrible mistake, it was wrong. All of us at Philip Morris,
no matter where we work, are extremely sorry for this. No one benefits
from the very real, serious and significant diseases caused by smoking."
Between 1970 and 1995, per-capita cigarette consumption in poorer
developing countries increased by 67 percent, while it dropped by 10
percent in the richer developed world. Eighty percent of smokers now
live in less developed countries. By 2030, the World Health Organization
(WHO) forecasts that 10 million people a year will die of
smoking-related illness, making it the single biggest cause of death
worldwide, with the largest increase to be among women. WHO forecasts
the 21st century's death rate from smoking to be ten times the 20th
century's rate ("Washingtonian" magazine, December 2007).
Health
Tobacco smoking is the leading cause of preventable death and a major public health concern.
There are 1.1 billion tobacco users in the world. One person dies every six seconds from a tobacco related disease.
Common adverse effects of tobacco smoking. The more common effects are in bold face.
Tobacco smoke is a complex mixture of over 7,000 toxic chemicals,
several of which 98 are associated with an increased risk of
cardiovascular disease and 69 of which are known to be carcinogenic. The most important chemicals causing cancer are those that produce DNA damage since such damage appears to be the primary underlying cause of cancer. Cunningham et al. combined the microgram weight of the compound in the smoke of one cigarette with the known genotoxic effect per microgram to identify the most carcinogenic compounds in cigarette smoke: acrolein, formaldehyde, acrylonitrile, 1,3-butadiene, acetaldehyde, ethylene oxide, and isoprene.
Cigarette smoking has also been associated with sarcopenia, the age-related loss of muscle mass and strength.
The World Health Organization estimates that tobacco caused 5.4 million deaths in 2004 and 100 million deaths over the course of the 20th century. Similarly, the United States Centers for Disease Control and Prevention
describes tobacco use as "the single most important preventable risk to
human health in developed countries and an important cause of premature
death worldwide." Although 70% of smokers state their intention to quit only 3–5% are actually successful in doing so.
The probabilities of death from lung cancer
before age 75 in the United Kingdom are 0.2% for men who never smoked
(0.4% for women), 5.5% for male former smokers (2.6% in women), 15.9%
for current male smokers (9.5% for women) and 24.4% for male "heavy
smokers" defined as smoking more than 5 cigarettes per day (18.5% for
women).
Tobacco smoke can combine with other carcinogens present within the
environment in order to produce elevated degrees of lung cancer.
The risk of lung cancer reduces almost from the first day someone
quits smoking. Healthy cells that have escaped mutations grow and
replace the damaged ones in the lungs. In the research dated December
2019, 40% of cells in former smokers looked like those of people who had
never smoked.
Rates of smoking have generally leveled-off or declined in the
developed world. Smoking rates in the United States have dropped by half
from 1965 to 2006, falling from 42% to 20.8% in adults. In the developing world, tobacco consumption is rising by 3.4% per year.
Smoking alters the transcriptome of the lung parenchyma;
the expression levels of a panel of seven genes (KMO, CD1A, SPINK5,
TREM2, CYBB, DNASE2B, FGG) are increased in the lung tissue of smokers.
Passive smoking
is the inhalation of tobacco smoke by individuals who are not actively
smoking. Second-hand smoke (SHS) is the collection of chemicals released
when the burning end is present, and environmental tobacco smoke (ETS)
or third-hand smoke
is the smoke that remains after the burning end has been extinguished.
Because of its negative implications, exposure to SHS has played a
central role in the regulation of tobacco products. Six hundred thousand
deaths were attributed to SHS in 2004. It also has been known to
produce skin conditions such as freckles and dryness.
In 2015, a meta-analysis found that smokers were at greater risk of developing psychotic illness. Tobacco has also been described an anaphrodisiac due to its propensity for causing erectile dysfunction.
Social
Famous smokers of the past used cigarettes or pipes as part of their image, such as Jean-Paul Sartre's Gauloises-brand cigarettes; Albert Einstein's, Douglas MacArthur's, Bertrand Russell's, and Bing Crosby's pipes; or the news broadcaster Edward R. Murrow's cigarette. Writers in particular seem to be known for smoking, for example, Cornell Professor Richard Klein's book Cigarettes are Sublime
for the analysis, by this professor of French literature, of the role
smoking plays in 19th and 20th century letters. The popular author Kurt Vonnegut addressed his addiction to cigarettes within his novels. British Prime Minister Harold Wilson was well known for smoking a pipe in public as was Winston Churchill for his cigars. Sherlock Holmes, the fictional detective created by Sir Arthur Conan Doyle, smoked a pipe, cigarettes, and cigars. The DCVertigo comic book character John Constantine, created by Alan Moore, is synonymous with smoking, so much so that the first storyline by Preacher creator Garth Ennis centered around John Constantine contracting lung cancer. Professional wrestlerJames Fullington, while in character as "The Sandman", is a chronic smoker in order to appear "tough".
The problem of smoking at home is particularly difficult for
women in many cultures (especially Arab cultures), where it may not be
acceptable for a woman to ask her husband not to smoke at home or in the
presence of her children. Studies have shown that pollution levels for
smoking areas indoors are higher than levels found on busy roadways, in
closed motor garages, and during fire storms. Furthermore, smoke can spread from one room to another, even if doors to the smoking area are closed.
The ceremonial smoking of tobacco, and praying with a sacred pipe, is a prominent part of the religious ceremonies of a number of Native American Nations. Sema, the Anishinaabe
word for tobacco, is grown for ceremonial use and considered the
ultimate sacred plant since its smoke is believed to carry prayers to
the spirits. In most major religions, however, tobacco smoking is not
specifically prohibited, although it may be discouraged as an immoral
habit. Before the health risks of smoking were identified through
controlled study, smoking was considered an immoral habit by certain
Christian preachers and social reformers. The founder of the Latter Day Saint movement, Joseph Smith, recorded that on 27 February 1833, he received a revelation
which discouraged tobacco use. This "Word of Wisdom" was later accepted
as a commandment, and faithful Latter-day Saints abstain completely
from tobacco.
Jehovah's Witnesses base their stand against smoking on the Bible's
command to "clean ourselves of every defilement of flesh" (2 Corinthians
7:1). The Jewish Rabbi Yisrael Meir Kagan (1838–1933) was one of the first Jewish authorities to speak out on smoking. In Ahmadiyya Islam, smoking is highly discouraged, although not forbidden. During the month of fasting however, it is forbidden to smoke tobacco. In the Baháʼí Faith, smoking tobacco is discouraged though not forbidden.
Incomes
One of
the largest global enterprises in the world is known to be the tobacco
industry. The six biggest tobacco companies made a combined profit of
$35.1 billion (Jha et al., 2014) in 2010.
Public policy
On 27 February 2005 the WHO Framework Convention on Tobacco Control,
took effect. The FCTC is the world's first public health treaty.
Countries that sign on as parties agree to a set of common goals,
minimum standards for tobacco control policy, and to cooperate in
dealing with cross-border challenges such as cigarette smuggling.
Currently the WHO declares that 4 billion people will be covered by the
treaty, which includes 168 signatories.
Among other steps, signatories are to put together legislation that
will eliminate secondhand smoke in indoor workplaces, public transport,
indoor public places and, as appropriate, other public places.
Taxation
Many governments have introduced excise taxes on cigarettes in order to reduce the consumption of cigarettes. The World Health Organisation finds that:
The structure of tobacco excise taxes varies considerably across
countries, with lower income countries more likely to rely more on ad valorem
excises and higher income countries more likely to rely more on
specific excise taxes, while many countries at all income levels use a
mix of specific and ad valorem excises.
Tobacco excise tax systems are quite complex in several countries,
where different tax rates are applied based on prices, product
characteristics such as presence/absence of a filter or length,
packaging, weight, tobacco content, and/or production or sales volume.
These complex systems are difficult to administer, create opportunities
for tax avoidance, and are less effective from a public health
perspective.
Globally, cigarette excise taxes account for less than 45 percent of
cigarette prices, on average, while all taxes applied to cigarettes
account for just over half of half of price. Higher income countries
levy higher taxes on tobacco products and these taxes account for a
greater share of price, with both the absolute tax and share of price
accounted for by tax falling as country incomes fall.
In 2002, the Centers for Disease Control and Prevention said that each pack of cigarettes sold in the United States costs the nation more than $7 in medical care and lost productivity,
around $3400 per year per smoker. Another study by a team of health
economists finds the combined price paid by their families and society
is about $41 per pack of cigarettes.
Substantial scientific evidence shows that higher cigarette
prices result in lower overall cigarette consumption. Most studies
indicate that a 10% increase in price will reduce overall cigarette
consumption by 3% to 5%. Youth, minorities, and low-income smokers are
two to three times more likely to quit or smoke less than other smokers
in response to price increases. Smoking is often cited as an example of an inelastic good, however, i.e. a large rise in price will only result in a small decrease in consumption.
Many nations have implemented some form of tobacco taxation. As
of 1997, Denmark had the highest cigarette tax burden of $4.02 per pack.
Taiwan only had a tax burden of $0.62 per pack. The federal government
of the United States charges $1.01 per pack.
Cigarette taxes vary widely from state to state in the United States. For example, Missouri has a cigarette tax of only 17 cents per pack, the nation's lowest, while New York
has the highest cigarette tax in the U.S.: $4.35 per pack. In Alabama,
Illinois, Missouri, New York City, Tennessee, and Virginia, counties and
cities may impose an additional limited tax on the price of cigarettes. Sales taxes are also levied on tobacco products in most jurisdictions.
In the United Kingdom, a packet of 20 cigarettes has a tax added of 16.5% of the retail price plus £4.90. The UK has a significant black market
for tobacco, and it has been estimated by the tobacco industry that 27%
of cigarette and 68% of handrolling tobacco consumption is non-UK duty
paid (NUKDP).
In Australia total taxes account for 62.5% of the final price of a
packet of cigarettes (2011 figures). These taxes include federal excise
or customs duty and Goods and Services Tax.
Restrictions
An enclosed smoking area in a Japanese train station. Notice the air vent on the roof.
In June 1967, the US Federal Communications Commission
ruled that programmes broadcast on a television station which discussed
smoking and health were insufficient to offset the effects of paid
advertisements that were broadcast for five to ten minutes each day. In
April 1970, the US Congress passed the Public Health Cigarette Smoking Act banning the advertising of cigarettes on television and radio starting on 2 January 1971.
The Tobacco Advertising Prohibition Act 1992 expressly prohibited
almost all forms of Tobacco advertising in Australia, including the
sponsorship of sporting or other cultural events by cigarette brands.
All tobacco advertising and sponsorship on television has been
banned within the European Union since 1991 under the Television Without
Frontiers Directive (1989).
This ban was extended by the Tobacco Advertising Directive, which took
effect in July 2005 to cover other forms of media such as the internet,
print media, and radio. The directive does not include advertising in
cinemas and on billboards or using merchandising – or tobacco
sponsorship of cultural and sporting events which are purely local, with
participants coming from only one Member State as these fall outside the jurisdiction of the European Commission.
However, most member states have transposed the directive with national
laws that are wider in scope than the directive and cover local
advertising. A 2008 European Commission report concluded that the
directive had been successfully transposed into national law in all EU
member states, and that these laws were well implemented.
Some countries also impose legal requirements on the packaging of
tobacco products. For example, in the countries of the European Union,
Turkey, Australia and South Africa, cigarette packs must be prominently labeled with the health risks associated with smoking.
Canada, Australia, Thailand, Iceland and Brazil have also imposed
labels upon cigarette packs warning smokers of the effects, and they
include graphic images of the potential health effects of smoking. Cards
are also inserted into cigarette packs in Canada. There are sixteen of
them, and only one comes in a pack. They explain different methods of
quitting smoking. Also, in the United Kingdom, there have been a number
of graphic NHS advertisements, one showing a cigarette filled with fatty deposits, as if the cigarette is symbolizing the artery of a smoker.
Some countries have also banned advertisement at point of sale.
United Kingdom and Ireland have limited the advertisement of tobacco at
retailers.
This includes storing of cigarettes behind a covered shelf not visible
to the public. They do however allow some limited advertising at
retailers. Norway has a complete ban of point of sale advertising.
This includes smoking products and accessories. Implementing these
policies can be challenging, all of these countries experienced
resistance and challenges from the tobacco industry.
The World Health Organisation recommends the complete ban of all types
of advertisement or product placement, including at vending machines, at
airports and on internet shops selling tobacco. The evidence is as yet unclear as to the impact of such bans.
Many countries have a smoking age.
In many countries, including the United States, most European Union
member states, New Zealand, Canada, South Africa, Israel, India,
Brazil, Chile, Costa Rica and Australia, it is illegal to sell tobacco
products to minors and in the Netherlands, Austria, Belgium, Denmark and
South Africa it is illegal to sell tobacco products to people under the
age of 16. On 1 September 2007 the minimum age to buy tobacco products
in Germany rose from 16 to 18, as well as in the United Kingdom where on
1 October 2007 it rose from 16 to 18.
Underlying such laws is the belief that people should make an informed
decision regarding the risks of tobacco use. These laws have a lax
enforcement in some nations and states. In China, Turkey, and many other
countries usually a child will have little problem buying tobacco
products, because they are often told to go to the store to buy tobacco
for their parents.
Several countries such as Ireland, Latvia, Estonia, the Netherlands, Finland, Norway, Canada, Australia, Sweden, Portugal, Singapore, Italy, Indonesia, India, Lithuania, Chile, Spain, Iceland, United Kingdom, Slovenia, Turkey and Malta
have legislated against smoking in public places, often including bars
and restaurants. Restaurateurs have been permitted in some jurisdictions
to build designated smoking areas (or to prohibit smoking). In the
United States, many states prohibit smoking in restaurants, and some
also prohibit smoking in bars. In provinces of Canada, smoking is
illegal in indoor workplaces and public places, including bars and
restaurants. As of 31 March 2008 Canada has introduced a smoke-free law
ban in all public places, as well as within 10 metres of an entrance to
any public place. In Australia, smoke-free laws vary from state to
state. Currently, Queensland has completely smoke-free indoor public
places (including workplaces, bars, pubs and eateries) as well as
patrolled beaches and some outdoor public areas. There are, however,
exceptions for designated smoking areas. In Victoria, smoking is restricted in railway stations, bus stops and tram stops as these are public locations where second-hand smoke
can affect non-smokers waiting for public transport, and since 1 July
2007 is now extended to all indoor public places. In New Zealand and Brazil,
smoking is restricted in enclosed public places including bars,
restaurants and pubs. Hong Kong restricted smoking on 1 January 2007 in
the workplace, public spaces such as restaurants, karaoke rooms,
buildings, and public parks (bars which do not admit minors were exempt
until 2009). In Romania
smoking is illegal in trains, metro stations, public institutions
(except where designated, usually outside) and public transport.
In Germany,
additionally to smoking bans in public buildings and transports, an
anti-smoking ordinance for bars and restaurants was implemented in late
2007. A study by the University of Hamburg (Ahlfeldt and Maennig 2010)
demonstrates, that the smoking ban had, if any, only short run impacts
on bar and restaurant revenues. In the medium and long run no negative
effect was measurable. The results suggest either, that the consumption
in bars and restaurants is not affected by smoking bans in the long run,
or, that negative revenue impacts by smokers are compensated by
increasing revenues through non-smokers.
Ignition safety
An
indirect public health problem posed by cigarettes is that of
accidental fires, usually linked with consumption of alcohol. Enhanced
combustion using nitrates was traditionally used but cigarette
manufacturers have been silent on this subject claiming at first that a
safe cigarette was technically impossible, then that it could only be
achieved by modifying the paper. Roll your own cigarettes contain no
additives and are fire safe. Numerous fire safe cigarette
designs have been proposed, some by tobacco companies themselves, which
would extinguish a cigarette left unattended for more than a minute or
two, thereby reducing the risk of fire. Among American tobacco
companies, some have resisted this idea, while others have embraced it. RJ Reynolds was a leader in making prototypes of these cigarettes in 1983 and will make all of their U.S. market cigarettes to be fire-safe by 2010. Phillip Morris is not in active support of it. Lorillard (purchased by RJ Reynolds), the US' 3rd-largest tobacco company, seems to be ambivalent.
Gateway drug theory
The relationship between tobacco and other drug use has been
well-established, however the nature of this association remains
unclear. The two main theories are the phenotypic causation
(gateway) model and the correlated liabilities model. The causation
model argues that smoking is a primary influence on future drug use,
while the correlated liabilities model argues that smoking and other
drug use are predicated on genetic or environmental factors.
One study published by the NIH found that tobacco use may be linked to
cocaine addiction and marijuana use. The study stated that 90% of adults
who used cocaine had smoked cigarettes before (this was for people ages
18–34). This study could support the gateway drug theory.
Cessation
Smoking cessation, referred to as "quitting", is the action leading
towards abstinence of tobacco smoking. Methods of "quitting" include
advice from physicians or social workers, cold turkey, nicotine replacement therapy, contingent vouchers, antidepressants, hypnosis, self-help (mindfulness meditation), and support groups. A meta-analysis from 2018, conducted on 61 RCT,
showed that one year after people quit smoking with the assistance of
first‐line smoking cessation medications (and some behavioral help),
only a little under 20% of smokers remained sustained abstinence.
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