The Hazards of Nicotine and Cigarette Smoking
Smoking and Its Effects: The Hazards of Nicotine and Cigarette Smoking
Background
The Tobacco Industry
Tobacco first came to be known when Christopher Columbus, an Italian explorer, received tobacco leaves as a gift from American Indians and brought it to Europe in the 1400’s. From that time to the early 1700’s, tobacco became widely popular increasing its value to that of gold and using it even as a medium of trade. The 16th-19th century saw the constant bloom of the Tobacco Industry then only producing and selling cigars. But it was in the early 20th century that the official cigarette which we now use until today made its debut into the market with an enormous 3.5 billion cigarettes sold, though still half the number of cigars that were sold, 6 billion. (Randall, 1999) This was the start of something big as companies such as Philip Morris and Marlboro, R.J. Reynolds and Camel, American Tobacco Company and Lucky Strike expanded their businesses reaching much of the world.
Cigarette smoking and its contents
All this of course happened without definite knowledge and scientific data of what exactly is a cigarette and why it is hard to stop the use and abuse of such a commodity. According to Jarvis, during the 20th century, cigarette smoking was seen as a social maturity and transformation into adulthood. It was a personal choice, with or without the person knowing the implications of the long-term effects of such a dangerous a habit. At present, however, it is already widely believed that the reason most people do cigarette smoking is because of nicotine addiction. (Jarvis, 2004)
The full effects and constituents of smoking and cigarettes were not established until the late 1900’s. Seeing as the only probable cause of addiction in the mixture is nicotine, the others, on the other hand, can produce much adverse effects that might be bad for the health.
With the discovery, however, the world was also beginning to see the outcomes of chronic cigarette smoking. There was a time in the mid 1980’s that lung cancer became the leading cause of mortality among women, greater than breast cancer. (Randall, 1999)
This is because not all contents of cigarette smoke have the pleasurable benefits of nicotine. Cigarettes emit smoke containing a complex mixture of chemicals. Cigarette smoke is generally classified as an aerosol suspension composed of: (1) gases such as carbon monoxide (CO), hydrogen cyanide (HCN), and nitrogen oxides, (2) volatile chemicals such formaldehyde, benzene, and nitrosamines, and (3) solid particles such as nicotine and phenol. (Harris, 1996, p. 59) Except for nicotine, most of these components are carcinogenic, which causes the development of cancer and produce a serious reaction to the body.
The Government
Because of these revelations, leaders all over the world started to take action going so far as banning commercials and prohibiting smoking in public places in an effort to reduce health effect. There were also conferences and meetings that have convened for the global eradication of tobacco use such as the WHO Framework Convention on Tobacco Control which started in 2006.
Effects of smoking: Nicotine
Beneficial effects of nicotine
Nicotine’s addictive property is mainly attributed to its effects on the brain. Nicotine is found to have high affinity to receptors found substantially throughout the brain with much of it occurring at the cortex and thalamus, parts of the brain responsible for stress adaption and sensory perception. A substantial amount of the receptors can also be found in the amygdale, septeum and brain stem motor nuclei. (Benowitz,1998, 4) Such binding also leads to the release of neurotransmitters like dopamine, serotonin, endorphins, which act as stimulants inducing pleasure and reducing stress and anxiety. (Benowitz, 2009, para. 8-10)
There is no doubt that nicotine in itself can produce valuable effects, when used in the right amount, in the human body. The meta-analysis conducted by Heishman and colleagues in 2010 gave much assurance to this theory. It has concluded that nicotine creates significant effects on motor abilities, attention, and memory. Aside from this, nicotine can also have effects in the enhancement of performances, reduction of body weight and protection against a number of diseases such as sleep apnea and ulcerative colitis. (Jarvik, 2006)
Furthermore, the isolation of pure nicotine made possible the conduction of several studies regarding the possible health benefits and/or hazards of nicotine, and by extension, tobacco use. Recent studies show that nicotine, in its pure form, has neuroprotective effects allowing for neurodegenerative disorders to be lower in people who were smoking than those who were not. The study by Ross and Petrovitch in 2001 showed that there is an inverse association between nicotine, through cigarette smoking, and Parkinson’s disease, a degenerative disorder characterized by progressive neuronal loss in the substantia nigra and decreased levels of dopamine.
The study also revealed that the increased levels of dopamine stimulated by the nicotine intake through tobacco were helpful in the improvement of motor functions in patients with Parkinsonism. This was evidenced by the “[preservation of] nigral neurons and striatal dopamine levels in the laboratory animals with lesioned nigrostriatal pathways” that were used in the study. (Ross & Petrovitch, 2001) Nicotine also has positive effects in diseases such as Alzheimer’s disease and Tourette’s syndrome.
Chronic and Toxic effects of nicotine
However, anything taken in excess can also produce harmful effects to the body. High concentrations of nicotine have been found out to produce significant effects such as tremors, emesis, and stimulation of the respiratory centers. Danger increases at greater concentrations causing fatal convulsions that may lead to coma. The fatal dose of nicotine is about 40mg or 1 drop of the pure liquid. (Katzung, 2009, p. 143)
All of these are acute effects of nicotine. Chronic effects, on the other hand, works in a much slower progression and is mainly caused by cigarette smoking. The onset of these effects is much delayed (i.e. years to decades) that it makes it less hard to convince people to stop their smoking. Though the exact contributions of nicotine to the adverse effects of cigarette smoking are still unknown up to the present, there were theories concerning nicotine and the risk of vascular diseases and sudden coronary death associated with smoking. (Katzung, 2009, p. 144)
Hazards of Cigarette Smoking
Behavioral aspects and Withdrawal symptoms
Eventually, once a person who practices chronic smoking such as 20 pack-days, it may not be easy to stop. Sooner, the brain develops an association between aspects of cigarettes and the pleasurable and relaxing effects of nicotine. A sight of the stick or the packet, the smell of the smoke, and some other senses that were used during cigarette smoking may automatically induce the brain to expect the pleasurable effects (Jarvis, 2004).
This phenomenon became a widespread concern between heavy smokers because the moment a smoker stops the habit, withdrawal symptoms emerge. These are signs and symptoms that are experienced by people in response to a lack of substance or activity that the body is normally accustomed to. Such is the case for stopping cigarette withdrawal, one may develop nicotine withdrawal. This is usually experienced by increase irritability, depressed mood, restlessness, anxiety, problems getting along with friends and family, difficulty concentrating, increased hunger and eating, insomnia and craving for tobacco (Benowitz, 2009).
It is believed that such a withdrawal is due to the lack of dopamine necessary to fill the large amount of receptors that were developed due to the initial influx of dopamine release as a result of much nicotine exposure. In extreme cases, nicotine withdrawal may produce mood disturbances similar to those in psychiatric patients and “hedonic dysregulation” (i.e. unable to find pleasure in certain activities or things in life), a common for most substances of abuse (Benowitz, 2009).
Effects on the immune system
For some time now, the effects of cigarette smoking has been largely associated with tobacco-smoke-induced changes in the immune and inflammatory system. The significant release of alveolar macrophages is believed to play a crucial role in the development of acute bronchoconstriction, which leads to airway inflammation, obstruction, and acute respiratory tract illnesses. There was also a noted increase in oxidative radicals and myeloperoxidase activity, which are important mediators of intracellular pathogen killing. (Sopori. 2002) While smokers can and might be protected from some diseases such as those of bacterial causes (e.g. Listeria monocytogenes, Staphylococcus aureus) due to alveolar macrophages, cigarette smokers are still not exempted from the danger of other more harmful bacteria like Pseudomonas aeruginosa.
Cigarette Disease Risk
Health hazards of smoking are mainly connected with heavy smoking, duration of smoking, and early start of smoking. Because cigarette smoke is mainly absorbed in the lungs, the greatest adverse effects are experienced in the respiratory system. One of the chronic effects of smoking is asthma. It has been found out that cigarette smoking can both increase the risk of developing asthma in healthy patients who smoke and accelerate exacerbations of asthma in those with the disease.
Studies show that smokers with asthma develop more severe symptoms up to 9-10 times greater than non-smokers due to its additional effects in acute bronchoconstriction. The study by Cassino et al. in 1999 (as cited in Thompson, Chaudhuri & Livingston, 2009) was able to correlate hospital visits among heavy cigarette smokers with asthma compared to those with none and concluded that admission rates are generally higher for the former. Several studies have also noted the fast decline in lung function for asthmatic smokers, which maybe associated to the higher mortality rate due to near-fatal asthma attack in smokers than non-smokers.
In addition, cigarette smoking can also pose significant drug interactions such as with corticosteroids, drugs mainly used in the management of asthma. This interaction, however, is still unclear and has varying conclusions in several studies. Regardless of the vagueness and lack of conclusion, smoking cessation is still widely recommended for those who have asthma.
Another pressing issue that concerns cigarette smokers is the development of lung cancer during the later years of life as a result of chronic exposure to cigarette smoke. As mentioned, nicotine is not the only substance being absorbed in the lungs, which enters the body, when cigarette smoke is inhaled. The International Agency for Researach on Cancer has identified at the very least 60 components of the more than 4,000 identified constituents of cigarette smoke to be carcinogenic, such as the presence of polyaromatic hydrocarbons (PAH) like benzene. This is believed to account for the high statistics of cancer seen in cigarette smokers. While the most prevalent of respiratory cancers seen is lung cancer, others such as oral, oropharyngeal, hypopharyngeal, laryngeal, and esophageal cancers can also be observed (Hecht, 2002).
Furthermore, though nicotine is not generally considered as carcinogenic, certain conditions may also convert it into carcinogenic substances in the body (Hecht, 2002). These carcinogens produce reactive substances that bind with the DNA in the body producing DNA adducts which may cause miscoding and mutation to appear in the body. Mutations in general are not helpful and may produce abnormalities. There is also the presence of tumors which may affect healthy cells in the body.
Second-hand smoking
What is most alarming is that not only cigarette smokers develop risk of lung cancer and diseases of the respiratory system, in recent years, questions have been arising on the effect of second-hand smoke, or the smoke released by a smoker which may be inhaled by a non-smoker or passerby, on an individual’s health. Separate studies have shown that second-hand smoke has a role in the worsening symptoms of asthma and the development of lung cancer.
In a study by Zhu and colleagues in 2003, an experiment concluded that second-hand smoke can significantly increase and promote tumor growth and angiogenesis. (Zhu, et al., 2003) Another study at the University of California have found out that inhalation of second-hand-smoke is related to greater severity of asthma and risk of hospital admissions due to exacerbations. (Eisner, et al., 2005) Second-hand smoke, which is mainly a mixture of sulfur dioxide, ammonia, formaldehyde and acrolein, can pose as a potent respiratory irritant in asthmatic patients.
Second-hand smoke was believed to cause a variety of illnesses other than lung cancer and asthma such as ischemic heart disease and lower respiratory infections. They not only affect adults but also cause illnesses in the young, with lower respiratory infections affecting children the most. These phenomena may attribute to the worldwide morbidity and mortality related to second-hand smoke. In a 2004 data, about 1.0% of the worldwide mortality was indirectly caused by second-hand smoke. 28% of the 603,000 deaths from second-hand smoke were children, while 47% were women and 26% men. These estimates have greatly concerned the public of the possible disease burden of second-hand smoke more than the smoking population. (Öberg, Jaakkola, Woodward, Peruga, Prüss-Ustün, 2010)
Passive smoking and Pregnancy
Aside from the non-smoking population, studies have also shown that pregnant mothers and mothers-to-be, who are habitual smokers before, during and after pregnancy, may endanger their child’s health care even from fetal level. (Hofhuis, de Jongste, & Merkus, 2003) Prenatal passive smoking was determined to have consequences in fetal development because harmful chemicals from cigarette smoke can cross placental barrier. Such effects may include low birth weight, and lung and brain development abnormalities. The development abnormalities may then result to a significant reduction in general intellectual ability and attention deficit and hypersensitivity disorder later on in childhood.
What may be the most severe effect of passive and environmental tobacco smoke in infants is its increased risked for sudden infant death syndrome (SIDS). SIDS, as the name implies is the unexpected, sudden death of an infant (<1 year old) where there is no visible signs or causes of death even after autopsy. A system review (as cited in Hofhuis, de Jongste, & Merkus, 2003, 1087) revealed that there is twice an increased risk for SIDS in infants whose mothers are smoking chronically. The positive relation is proven to be dose dependent and causal.
Smoking cessation
These critical effects paved the way to vigorous counseling of the tapering and eventual termination of the habit and the development of interventions that can achieve such goals. One such intervention widely promoted at present is Nicotine Replacement Therapy (NRT). This treatment is based on the assumption, and somehow fact, that tobacco addiction is mainly due to the pleasant effects of nicotine contained in cigarette. As such, it enables and facilitates smoking cessation by substituting tobacco with its other harmful constituents to products containing only nicotine like nicotine patches, gums, inhalers and lozenges. (Benowitz, 2004This was primarily developed to avoid the traumatizing effects of tobacco withdrawal which is largely manifested as nicotine withdrawal symptoms of restlessness and anxiety.
Probably a widely used mode of delivery, especially for heavy smokers, is through nicotine patches. The effectiveness of this route is mainly due to its inherent capability to act on the root cause of addiction, which is the binding of the substance to nicotinic receptors. Sustained release of nicotine provided by patches allows for desensitization of these nicotinic receptors, wherein occurrence of binding will not produce the same level of effects previously experienced with nicotine thereby reducing the satisfaction brought by cigarettes. Other seemingly and possible effective treatments are the use of Bupropion, Varenicline, and the drug Rimonabant, which is currently under development. (Benowitz, 2009)
Conclusion
There is no doubt that nicotine is a substance that produces pleasurable and relaxing effects to the body making individuals capable of coping to stress and work fatigue. It may also prove to be significant in the treatment of certain neurodegenerative disorders such as Parkinson’s and Alzheimer’s diseases due to its neuroprotective effects. However, these benefits are said to be only short-lived and may lead to substance addiction. Chronic and toxic use of nicotine still poses significant health risks, the most serious of which is coma.
Nicotine addiction resulting to cigarette smoking, on the other hand, is a more pressing issue which not only affects individual smokers but also those around them. It has proven implications on respiratory disease development and exacerbation such as asthma and lung cancer, and other systems disease such as coronary heart disease risks and immunosuppression.
Effect on non-smokers also prove the gravity of the habit wherein passive smokers through second-hand smoke in children and adults and placental transfer in infancy. Studies have shown that second-hand smokers develop more risk for morbidity and mortality to respiratory diseases, especially lung cancer, later on in life due to the components of residuals emitted when cigarette smoke is exhaled. It also has proven fatal probabilities in infants due to a correlation between maternal smokers and occurrences of SIDS.
With these advancements in research regarding cigarettes and smoking, governments and concerned organizations would like to hope that there will come a time that the world may be rid of cigarette smoking and, maybe by extension nicotine addiction. Though the industry is still a long way from quitting production of such a multi-million dollar commodity and investment, combined efforts from the society and the individual may ensure that these undesired effects may lessen over time. The habit may be physically induced, but cessation is more psychologically and socially stimulated.
References
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