Animals are exposed to tobacco smoke and other cigarette by-products through their use as experimental subjects and through contact with smokers, as in the case of pets in houses where smoking takes place.
Animals are exposed to tobacco smoke and other cigarette by-products through their use as experimental subjects and through contact with smokers, as in the case of pets in houses where smoking takes place.
The first recorded attempts to artificially induce animal tumors through the application of tobacco products occurred in 1911. [1] A 2004 series of monographs released by the International Agency for Research on Cancer, a part of the World Health Organisation, summarized research from the 1960s onwards about the carcinogenicity of tobacco on various laboratory animals. [1]
As set out in the IARC monographs, the carcinogenicity of cigarette smoke is determined in two ways. The first is through the application of cigarette-smoke condensates to skin. Cigarette-smoke condensates are collected by passing smoke through cold traps and recovering the retained material. The cigarettes are usually machine-smoked and the material is washed from the traps using a volatile substance such as acetone, which is then removed. Many of the procedures for collecting this cigarette-smoke-condensate have not yet been standardized across laboratories, including how the condensate is stored, in what numbers and fashion the cigarettes are smoked, and the type of solvent used. Once the condensate is collected, it is painted onto the skin of the animal test subjects, which are then examined at set intervals to assess the growth of tumors.
The second method, as described by the IARC monographs, used to measure the carcinogenicity of cigarette smoke to animals is by exposing them to mainstream cigarette smoke. The IARC monographs define mainstream cigarette smoke as that which is emitted by the mouth end of the cigarette and therefore the smoke that human smokers would be exposed to most. The IARC monographs describe the methods and equipment that scientists have developed to make more effective and standardize the deliverance of mainstream cigarette smoke. These devices vary between whole-body and nose-only exposure, but typically involve machine smoked cigarette smoke being pumped into a small chamber that contains the animal test subjects. A variety of factors differentiate the experience of a human smoker from these animal test subjects'. Human smokers inhale smoke voluntarily and therefore do so more deeply than do animal test subjects which typically adopt short, shallow breaths when exposed to smoke. The animal test subjects, primarily rodents and dogs, also have significantly morphologically different upper respiratory system from humans. Despite these variables, the doses of smoke administered to these animals can be determined by examining tissue and blood samples. Dogs, which cannot be exposed to cigarette smoke via inhalation chambers as easily as can small rodents, require different methods of cigarette smoke exposure. These methods include thracheostomy, in which smoke is pumped through a tube directly into a hole cut in the dog's throat, or through a mask fitted to the dog's face. [1]
The IARC monographs concluded that the application of cigarette-smoke condensates onto the skin of mice induces tumors, of both benign and malignant variety. Although the carcinogenicity of tobacco smoke was first established in humans, various types of animals have also been exposed to tobacco smoke inhalation in attempts to yield further experimental proof and control for various experimental factors, including types of tobacco and levels of exposure, which would be considered unethical in human studies. The IARC monographs, referencing studies which used various methods of smoke inhalation, concluded that a significantly greater number of pulmonary tumors occurred among mice exposed to smoke than those in the control groups. Since the 1960s, the animal most used in testing the carcinogenicity of tobacco smoke has been the Syrian Golden Hamster due to its resistance to pulmonary infections and the infrequency with which it spontaneously develops pulmonary tumors. [1] According to the IARC monographs these studies have proven, and repeatedly confirmed, the carcinogenicity of tobacco smoke for hamsters.
Some studies referenced in the IARC monographs found that certain, but not all, groups of rats exposed to mainstream smoke were significantly more likely to develop lung tumors. The IARC monographs also referenced studies involving rabbits and dogs that were much less conclusive. The authors, however, cited various experimental limitations, such as small test or control groups and missing data, that could account for the lack of conclusive results. [1]
Multiple studies have also been conducted to determine the carcinogenicity of environmental tobacco to animals. These studies typically fall under the categories of simulated environmental tobacco, administering condensates of sidestream smoke, or observational studies of cancer among pets.
To study the consequences of passive smoking, scientists expose animals to sidestream smoke, that which emanates from the cigarette's burning cone and through its paper, or a combination of mainstream and sidestream smoke. [1] The IARC monographs conclude that mice with prolonged exposure to simulated second-hand smoke, that is six hours a day, five days a week, for five months with a subsequent four-month interval before dissection, will have significantly higher inicidence and multiplicity of lung tumors than with control groups.
The IARC monographs concluded that sidestream smoke condensates had a significantly higher carcinogenic effect upon mice than did mainstream smoke condensates. [1]
Second-hand smoke is recognized as a risk factor for cancer in pets. [2] A study conducted by the Tufts University School of Veterinary Medicine and the University of Massachusetts Amherst linked the occurrence of feline oral cancer to exposure to environmental tobacco smoke through an overexpression of the p53 gene. [3] Another study conducted at the same universities concluded that cats living with a smoker were more likely to get feline lymphoma; the risk increased with the duration of exposure to second-hand smoke and the number of smokers in the household. [4] A study by Colorado State University researchers, looking at cases of canine lung cancer, was generally inconclusive, though the authors reported a weak relation for lung cancer in dogs exposed to environmental tobacco smoke. The number of smokers within the home, the number of packs smoked in the home per day, and the amount of time that the dog spent within the home had no effect on the dog's risk for lung cancer. [5]
In 1990, a tobacco-industry researcher in Germany proposed a study of the effects on animals of lifetime exposure to second-hand smoke. The proposed study was blocked by Philip Morris, [6] as described in an internal company report:
PM [Philip Morris] recently succeeded in blocking Adlkofer's plan to conduct lifetime animal inhalation study of sidestream smoke. (... an INBIFO study has shown that in 90-day inhalation test, no non-reversible changes has [ sic ] been detected. In a lifetime study, the results were almost certain to be less favorable. Based on the analysis, the other members of the German industry agreed that the proposed study should not proceed). [7]
A 2008 study conducted by the Henry Ford Health System found that given information about the harmful effects of passive smoking on their pets, 28.4% of pet owners who smoke would be motivated to quit, 8.7% would ask those who live with them to quit, and 14.2% would stop smoking indoors. [8]
Animals like dogs, cats, squirrels, and other small animals are affected not only by second-hand smoke inhalation, but also nicotine poisoning.[ citation needed ] Domestic pets, especially dogs, usually fall ill when owners leave nicotine products like cigarette butts, chewing tobacco, or nicotine gum within reach of the animal.[ citation needed ] Littered cigarette butts from smokers can be a problem for small animals which mistake them for food if they find them, particularly in urban environments.[ citation needed ] Cigarette butts are the remains of a cigarette after smoking which contain the filter which is meant to contain tar, particles, and toxins from the cigarette such as ammonia, arsenic, benzene, turpentine and other toxins.[ citation needed ]
Cigarette butts can be found in high quantities as litter. It can take 18 months to 10 years for the filter to degrade. [9] Although cigarette litter awareness campaigns [10] encourage smokers to avoid littering and to even carry pocket ashtrays, cigarette butts rank number one on the list of worst litter problems in the U.S. This makes it easy for small animals like puppies, squirrels, and raccoons to find and unsuspectingly consume nicotine. A reported 4.5 trillion cigarette butts wind up as litter worldwide per year. Cigarette butts reportedly account for 30% of the waste items found on U.S. shorelines. [11]
This can be a hazard to animals like seagulls and turtles because when placed in large bodies of water like oceans, the toxins of the cigarette butt can be detrimental to marine life. Researchers at San Diego State University claim that filter-tipped cigarette butts are toxic especially for marine and fresh-water fish. [12] Even just one cigarette butt alone soaking in water for a day is hazardous enough to kill 50% of fish in a litre of water. [13] Dolphins have the most blubber in the marine life and toxins concentrate there, thus dolphins especially are the most affected by the toxins. [14]
The toxins of the cigarette butt can cause health problems in animals like vomiting, tremors and hypersalivation. Veterinary Medicine published a case of a 10-year-old female Labrador retriever ingesting cigarette butts. The Labrador vomited several times and had increased blood urea nitrogen, total protein, and albumin concentrations with hemolysis and lipemia also observed. [15] Apomorphine hydrochloride and activated charcoal had to be administered along with other fluids. 5 days after the incident, the dog's health returned to normal. The toxic level of nicotine in a dog or cat is reported as 20–100 mg which is about one to five cigarettes.
A newer product available in some markets, nicotine dissolvables, contains about 1 mg of nicotine per pellet. Other products like Camel Strips which contain 0.6 mg of nicotine per strip and sticks. [16] Though this nicotine content is low in comparison to a cigarette, these items can be more attractive to unwary small animals like puppies.
Much controversy exists over animal testing especially with nicotine and tobacco products. Animal activism groups are especially vocal about claims of companies like Phillip Morris funding animal tobacco research. There has always been much tension between animal activists groups, and researchers and this became especially visible with the serious attack against a researcher. Edythe D. London, a UCLA professor leading a 3-year study was targeted by activists and her home was flooded by the Animal Liberation Front. A fire-bomb was also left in front of her house by the North American Animal Liberation. [17] After the incident Edyth London wrote an article titled "Why I use animals in my research". [18] In the article, London expressed an interest in solving the problem of addiction and offering help to those who need help in quitting their tobacco addiction. She did admit to being funded by Philip Morris USA and sees no problem with it.
On the Philip Morris website [19] the company claims that they do not presently conduct internal research with the use of laboratory animals. They do fund external research, but claim to do so in a humane and responsible manner as shown by their accreditation by the Association for Assessment and Accreditation of Laboratory Animal Care.
In 2001, American Spirit claimed to have turned to cruelty-free cigarettes in which the company doesn't conduct cigarette testing using animals. [20] This move was praised by animal activists groups and used to encourage other tobacco companies to follow the leadership of American Spirit.
The main argument of animal activists, besides the ethical treatment of animals, is there is no point in continuing to perform these experiments on animals to prove the detrimental effects of tobacco, which are already known. The Impact Press like claims that "in one experiment, vivisectors cut holes in beagles' throats and made them breathe concentrated cigarette smoke for an entire year". [21] The group also claims that at the Oregon Regional Primate Research Center, the rhesus monkeys live in tight, metal cages and pregnant monkeys are exposed to nicotine. There is also disapproval by animal activists of a March of Dimes funded study in which nicotine was given to pregnant rats, and then the offspring were tested to see how they performed in a maze". [22] Groups like PETA are using slogans like "Don't get burned by Philip Morris. They're using your money to hurt animals". PETA also claims that there is still a question as to the reliability of results from animal testing for tobacco studies. According to an article, federal regulatory and research agencies have almost 200 test methods which guarantee effectiveness in animal studies. [23] The Interagency Coordinating Committee on the Validation of Alternative Methods exists to review these methods. Some researchers, however, continue to argue that there are longitudinal studies of cigarette-smoking which still need to be conducted, and that animal studies are not superfluous, but necessary.
A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substances are considered carcinogens, but their carcinogenic activity is attributed to the radiation, for example gamma rays and alpha particles, which they emit. Common examples of non-radioactive carcinogens are inhaled asbestos, certain dioxins, and tobacco smoke. Although the public generally associates carcinogenicity with synthetic chemicals, it is equally likely to arise from both natural and synthetic substances. Carcinogens are not necessarily immediately toxic; thus, their effect can be insidious.
Nicotine is a naturally produced alkaloid in the nightshade family of plants and is widely used recreationally as a stimulant and anxiolytic. As a pharmaceutical drug, it is used for smoking cessation to relieve withdrawal symptoms. Nicotine acts as a receptor agonist at most nicotinic acetylcholine receptors (nAChRs), except at two nicotinic receptor subunits where it acts as a receptor antagonist.
A cigarette is a narrow cylinder containing a combustible material, typically tobacco, that is rolled into thin paper for smoking. The cigarette is ignited at one end, causing it to smolder; the resulting smoke is orally inhaled via the opposite end. Cigarette smoking is the most common method of tobacco consumption. The term cigarette, as commonly used, refers to a tobacco cigarette, but the word is sometimes used to refer to other substances, such as a cannabis cigarette or an herbal cigarette. A cigarette is distinguished from a cigar by its usually smaller size, use of processed leaf, and paper wrapping, which is typically white. Most modern cigarettes are filtered, although this does not make the smoke inhaled from them contain fewer carcinogens and harmful chemicals.
Tobacco smoke is a sooty aerosol produced by the incomplete combustion of tobacco during the smoking of cigarettes and other tobacco products. Temperatures in burning cigarettes range from about 400 °C between puffs to about 900 °C during a puff. During the burning of the cigarette tobacco, thousands of chemical substances are generated by combustion, distillation, pyrolysis and pyrosynthesis. Tobacco smoke is used as a fumigant and inhalant.
Smoking bans, or smoke-free laws, are public policies, including criminal laws and occupational safety and health regulations, that prohibit tobacco smoking in certain spaces. The spaces most commonly affected by smoking bans are indoor workplaces and buildings open to the public such as restaurants, bars, office buildings, schools, retail stores, hospitals, libraries, transport facilities, and government buildings, in addition to public transport vehicles such as aircraft, buses, watercraft, and trains. However, laws may also prohibit smoking in outdoor areas such as parks, beaches, pedestrian plazas, college and hospital campuses, and within a certain distance from the entrance to a building, and in some cases, private vehicles and multi-unit residences.
Passive smoking is the inhalation of tobacco smoke, called passive smoke, secondhand smoke (SHS) or environmental tobacco smoke (ETS), by individuals other than the active smoker. It occurs when tobacco smoke diffuses into the surrounding atmosphere as an aerosol pollutant, which leads to its inhalation by nearby bystanders within the same environment. Exposure to secondhand tobacco smoke causes many of the same diseases caused by active smoking, although to a lower prevalence due to the reduced concentration of smoke that enters the airway.
Cotinine is an alkaloid found in tobacco and is also the predominant metabolite of nicotine, typically used as a biomarker for exposure to tobacco smoke. Cotinine is currently being studied as a treatment for depression, post-traumatic stress disorder (PTSD), schizophrenia, Alzheimer's disease and Parkinson's disease. Cotinine was developed as an antidepressant as a fumaric acid salt, cotinine fumarate, to be sold under the brand name Scotine, but it was never marketed.
Tar is the name for the resinous, combusted particulate matter made by the burning of tobacco and other plant material in the act of smoking. Tar is toxic and damages the smoker's lungs over time through various biochemical and mechanical processes. Tar also damages the mouth by rotting and blackening teeth, damaging gums, and desensitizing taste buds. Tar includes the majority of mutagenic and carcinogenic agents in tobacco smoke. Polycyclic aromatic hydrocarbons (PAH), for example, are genotoxic and epoxidative.
N-Nitrosonornicotine (NNN) is a tobacco-specific nitrosamine produced during the curing and processing of tobacco.
Tobacco products, especially when smoked or used orally, have negative effects on human health. Researchers have addressed concerns about these effects for a long time. They have focused primarily on cigarette smoking.
A cigarette filter, also known as a filter tip, is a component of a cigarette, along with cigarette paper, capsules and adhesives. Filters were introduced in the early 1950s.
Herbal cigarettes are cigarettes that usually do not contain any tobacco or nicotine, instead being composed of a mixture of various herbs and/or other plant material. However, Chinese herbal cigarettes contain tobacco and nicotine with herbs added, unlike European and North American herbal cigarettes which have tobacco and nicotine omitted. Like herbal smokeless tobacco, they are often used as a substitute for standard tobacco products. Herbal cigarettes are often advertised as a smoking cessation aid. They are also used in acting scenes by performers who are non-smokers, or where anti-smoking legislation prohibits the use of tobacco in public spaces. Herbal cigarettes can carry carcinogens.
Sidestream smoke is smoke which goes into the air directly from a burning cigarette, cigar, or smoking pipe. Sidestream smoke is the main component of second-hand smoke (SHS), also known as Environmental Tobacco Smoke (ETS) or passive smoking. The relative quantity of chemical constituents of sidestream smoke are different from those of directly inhaled ("mainstream") smoke, although their chemical composition is similar. Sidestream smoke has been classified as a Class A carcinogen by the U.S. Environmental Protection Agency.
In molecular genetics, a DNA adduct is a segment of DNA bound to a cancer-causing chemical. This process could lead to the development of cancerous cells, or carcinogenesis. DNA adducts in scientific experiments are used as biomarkers of exposure. They are especially useful in quantifying an organism's exposure to a carcinogen. The presence of such an adduct indicates prior exposure to a potential carcinogen, but it does not necessarily indicate the presence of cancer in the subject animal.
Tobacco harm reduction (THR) is a public health strategy to lower the health risks to individuals and wider society associated with using tobacco products. It is an example of the concept of harm reduction, a strategy for dealing with the use of drugs. Tobacco smoking is widely acknowledged as a leading cause of illness and death, and reducing smoking is vital to public health.
Third-hand smoke is contamination by tobacco smoke that lingers following the extinguishing of a cigarette, cigar, or other combustible tobacco product. First-hand smoke refers to what is inhaled into the smoker's own lungs, while second-hand smoke is a mixture of exhaled smoke and other substances leaving the smoldering end of the cigarette that enters the atmosphere and can be inhaled by others. Third-hand smoke or "THS" is a neologism coined by a research team from the Dana–Farber/Harvard Cancer Center, where "third-hand" is a reference to the smoking residue on surfaces after "second-hand smoke" has cleared out.
Ventilated cigarettes are considered to have a milder flavor than regular cigarettes. These cigarette brands may be listed as having lower levels of tar ("low-tar"), nicotine, or other chemicals as "inhaled" by a "smoking machine". However, the scientific evidence is that switching from regular to light or low-tar cigarettes does not reduce the health risks of smoking or lower the smoker's exposure to the nicotine, tar, and carcinogens present in cigarette smoke.
The use of electronic cigarettes (vaping) carries health risks. The risk depends on the fluid and varies according to design and user behavior. In the United Kingdom, vaping is considered by some to be around 95% less harmful than tobacco after a controversial landmark review by Public Health England.
The scientific community in the United States and Europe are primarily concerned with the possible effect of electronic cigarette use on public health. There is concern among public health experts that e-cigarettes could renormalize smoking, weaken measures to control tobacco, and serve as a gateway for smoking among youth. The public health community is divided over whether to support e-cigarettes, because their safety and efficacy for quitting smoking is unclear. Many in the public health community acknowledge the potential for their quitting smoking and decreasing harm benefits, but there remains a concern over their long-term safety and potential for a new era of users to get addicted to nicotine and then tobacco. There is concern among tobacco control academics and advocates that prevalent universal vaping "will bring its own distinct but as yet unknown health risks in the same way tobacco smoking did, as a result of chronic exposure", among other things.
A heated tobacco product (HTP) is a tobacco product that heats the tobacco at a lower temperature than conventional cigarettes. These products contain nicotine, which is a highly addictive chemical. The heat generates an aerosol or smoke to be inhaled from the tobacco, which contains nicotine and other chemicals. HTPs may also contain additives not found in tobacco, including flavoring chemicals. HTPs generally heat tobacco to temperatures under 600 °C (1100 °F), a lower temperature than conventional cigarettes.