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Tobacco is a risky business, but only for the smokers!

Tobacco companies make a lot of money from the addictive products that they push.  They are not about to go  bankrupt.  Statistics Canada reports an average of about 29%  smokers in the general population.

SEE THIS SITE OF STATISTCS CANADA! Click here

This is an even bigger problem in the younger population.  It is a common fact that cigarettes are bad for you, but not many people actually know how bad and why.  What actually happens in your brain when you smoke? What are the physiological effects on your body when you light up?

There is a very interesting history to how we were able to prove with statistical tools that cigarettes are dangerous. There is a very strong correlation between smoking and cancer, but it wasn’t easy proving that until the appropriate tools were established to prove that.

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 This website is divided into 4 topics related to smoking, click on the titles below to know more about it:

- The History of Statistics and Smoking

- The Effects of Nicotine on the Brain

- Smoking and your lungs

-Smoking and Stress

The History of Statistics

    Insurance companies were the first to actually want to proove empirically that tobacco is hazardous to your health.  Indeed, they noticed that they were losing money and they needeed concrete proof that smokers were at risk to higher their premiums.

    Brown (1978) reports it was a great problem to drawing valid scientific conclusions from the accumulating reports of the harmful effects of smoking. (see information on Professor Brown's research by clicking here)

    How could we hold constant the variables under study when the variable under study is so elusive.  Indeed smoking behavior is hard to control and the reports were full of "uncontrolled, or partially controlled factors that cause unwanted variation in the data." It was very hard to apply to medical or biological sciences the statistical principles developed in physics.  It is thanks to greats like Galton, Fisher and Pearson that the link between smoking and cancer were further explored as they developed the adequate tools to study the phenomenon.

    Muller (1939) was the first to publish a study that attempted to use cointrol groups to study the hazardous effects of tobacco.  He matched lung cancer patients with people of the same age, sex and other similar characteristics.  He found much more smoking among the lung cancer patients.  The problem with this study is that the control group could only be chosen quite arbitrarily and not much could actually be inferred from such a study.

    Pearl (1938) was a statistician at John Hopkins University and had been keeping records of hundreds of families in the baltimore area.  Pearl constructed a table comprised of three groups: non smokers, moderate smokers and heavy smokers.  "His data showed that 65% of the non smokers lived to age 60, whereas only 45% of the heavy smokers lived that long.  But the problem is that both of these studies are retrospective, that is they are both looking back at the accomplished fact and do not really control for extraneous variables.  It was felt that a study where two groups were studied over time was needed.  As brown points out, what if it was simply that people who like smoking are more prone to cancer genetically and people who do not like it are not? Indeed, this could be a possible explanation for the data.

  It was Fisher and Berkson who in the sixties defended the tobacco industry saying that these tests must be interpreted with caution.  They were not really trying to say smoking is safe, only they were saying that the scientific methodology had to be revised.  "Berkson's main point was that the apparent ill effects of smoking were too pervasive." Berkson thought there were probably biases in the selection of subjects, especially since there were no theories explaining how tobacco caused all the ills it was associated with.  The problem is that the questions raised by Fisher and Berkson needed randomized experiments to be answered, which is a real ethical problem.  Indeed how could we in our right minds allocate people to smoking and non smoking groups if we have a doubt that it may be a lethal habit?

    Probably due to their influence much research was conducted on animals and smoking in the sixties.  It was less ethically complicated to allocate randomly animals to smoking or non smoking conditions.  It was found that tobacco smoke did cause many lesions in animal tissue.  In 1963 an advisory committee for the US public health service and the surgeon general reported that smoking was a cause of cancer and several other cancers, and that it should act on this presumption.  (cited from: Brown B.W, Jr. (1978) Statistics, Scientific Method and Smoking, Stanford University School of Medicine, pp59-69

     As Nachman (1995) explains in his article there is a direct effect of nicotine on the central nervous system. Nicotine produces a dose-dependent increase in cerebral glucose uptake.
Check out these web sites that discusse nicotine and the brain:

This web site discusses Nachman's  research: click here
This web site is devoted to NISE web site research

The subject covered in this section are:

 -Nicotine and the central nervous system
 -Nicotine absortion
 -Nicotine Tolerance and withdrawal

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NICOTINE AND THE CENTRAL NERVOUS SYSTEM

    Nicotine's effects on the central nervous system is shown in terms of neuroregulatory parameters.  There are dose dependent effects on neuroendochrine functions, this further shows the direct effects of nicotine on brian biochemistry neuroendocrinology it reinforces self-administrtation and addiction, says Nachman.
      Nachman quotes Pomerleau et al. They have shown that dose related administration nicotine causes the release of endogenous opiods in both hippocampal regions and hypothalamus.
     Nachman explains that these effects on the brain create feelings of pleasure and enhancement of pleasure when smoking a cigarette for addicts due to increased levels of dopamine, norepinephrine, and beta endorphin levels.  There is also a feeling of enhancement of performancebecause of the elevation of actyl-choline, and norepinephrine, vasopressin.  These chemical agents in the brain give the smoker the impression of a surge of creativity and cognitive performance. There is also a real improvement of memory in the smoker due to direct effects of actylcjoline on the brain.  Although these chemical substances actually do that for the smoker, the truth is that the smoker's peak in creativity is so short that it is wrong to think this increase in performance, memory or creativity will ctually have an effect on the work being done by the smoker.
     Smokers eventually have to take larger and more frequent amounts of nicotine to reach the same effects.  Nicotine stimulates the effect of dopamine, nicotine has been shown to more than double the level of dopamine in the brain of rats.  The problem is that with time, the effects of nicotine become weaker and it takes more and more nicotine to reach the same effects.  Nicotine binds itself at the cell body.

NISE web site research
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NICOTINE ABSORBTION

    Nicotine is an amine, explains Nachman.  It cannot be absorbed  through the cell membrane in the mouth at the ph of smoke.  From the oral cavity it is inhaled into the smoker's lung.  There the nicotine can be absorbed through pulmonary capillary blood flow.  Once the nicotine is absorbed through the alveolar blood flow, nicotine levels quikly rise in the blood.  It takes only 19 seconds from the time you inhale to the delivery of the nicotine to the brain.  The concentration of nicotine in the brain declines as nicotine is sent to ther body organs.  It is clear that nicotine is a quick acting drug, it's rapid distribution to the brain allow the rapid psychological and behavioral effects of nicotine on the brain.
 

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 NICOTINE TOLERANCE AND WITHDRAWAL

    Each cigarette you smoke creates a greater level of tolerance in your body to nicotine.  This tolerance effects does ware off however after a few hours of not smoking.  That is why smokers report that the first cigarette of the day is so strong or satisfying.  That first cigarette of the day produces substantial pharmacological effects, primarily arousal, but at the same time, says Nachman, tolerance begins to develop.  The euphoric effects of  each cigarette lessens throughout the day, making each cigarette les and less satisfying and the withdrawal symptoms more and more pronounced.

Smoking and your Lungs

    The positive effects of nicotine on the brain (such as memory and performance improvements) are irrelevnt when you realise the horrible efects it has on lungs and health. The stress levels rise  See the section on stress in APA journals .    The nicotine is carried in the the smoke inhaled by the lungs.

    As  explained in the section on the effects of nicotine on the brain, the drug is absorbed through the lung's cell membrane.  This has very gruesome and deadly effects on the health of the lungs.  The lungs get covered with tar, carbon monoxide, cyanide, benzene and many other toxic agents.  These agents are poisonous and every cigarette you smoke increases your chance of getting lung cancer and many other forms of cancer.

    Smoking causes mutations in the genes that control the way cells mature and divide.  The thousands of chemicals in cigarettes act on the DNA of the cell which chanes it's behaviour. Normally a cell only reproduces when it receives an order to do so, and it stops when it receives the order to stop reproducing from the body.  It should stay in contact with other cells of it's kind to form a tissue.  When the normal genes are damaged the cell becomes atypical and with time and exposure to more cancerous material then it becomes dysplastic. Dr. Auerbach documented the changes that occur in cells i dogs that were exposed to smoke from cigarettes. The cells continue to multiply in an erratic way, which eventually turns into a cancer.  There are many sites of interest on the internet dthat discuss the issue of smoking and lung Cancer.

    A study conducted by A.C. Parrot reports (click here to see his full report) that smokers feel a reduction of stress when they smoke.  He found that the stress levels of smokers was actually higher than non smokers however.  Indeed, the stress levels increase as the smokers develop a regular smoking habit.  He also found that smoking cessation actually lead to a cessation of stress.
    "Far from acting as a mood control, nicotine dependency actually seems to exacerbate stress".  The smoker's mood is normal during smoking, and is stressed when not smoking.   That means that for a smoker to feel normal, the smoker must alway have a lit cigarette in his mouth!
    Smoking only seems to reflect the reversal effect of of the tension and stress caused by the lack of nicotine in the blood.  Tobacco actually increases stress, and relieves it when you smoke.
    I think this means that smoking is kind of like hitting yourself over the head with a hammer because it feels really good when you stop!
    Indeed, stress is reduced in a really significant way when the smoker quits smoking.  Longitudinal and pospective studies have shown poor moods during the first few weeks after cessation, but there is drastic improvement once the nicotine is completely gne from the body, reducing craving for the drug and the stress that results from it.

1) http://www.statcan.ca/english/Pgdb/People/Health/health07a.htm
Statistics Canada
 

2)http://www.smi.stanford.edu/academics/faculty8.html
Stanford Educational Journals

3) Brown B.W, Jr. (1978) Statistics, Scientific Method and Smoking, Stanford University School of Medicine, pp59-69
quoted from Psy 113b, Research Methods Required Course Readings, Compiled by Staurt J. McKelvie, Lennoxville, QC

4) http://student.biology.arizona.edu/honors96/group7/studies.htm
Student Honor's Thesis
 

5) http://whyfiles.org/024nicotine/brainscan.html
 

6) http://www.apa.org/journals/amp/amp5410817.html
APA Journals Online Files
Does Cigarette Smoking Cause Stress?
Andy C. Parrott (1999)Does Cigarette Smoking Cause Stress? American Psychologist, Vol. 54, No. 10, 817–820
 

7) Nachman, B (1995) Direct Effects of Nicotine on the Brain: Evidence for Chemical Addiction, Archives of Environmental Health, Jul/Aug95, Vol. 50 Issue 4, p263, 4p
 

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