Health risks of smoking :

The main health risks in tobacco pertain to diseases of the cardiovascular system, in particular myocardial infarction (heart attack), cardiovascular disease, diseases of the respiratory tract such as Chronic Obstructive Pulmonary Disease (COPD), asthma, emphysema, and cancer, particularly lung cancer and cancers of the larynx and tongue.

A person's increased risk of contracting disease is directly proportional to the length of time that a person continues to smoke as well as the amount smoked. However, if someone stops smoking, then these chances gradually decrease as the damage to their body is repaired. A year after quitting, the risk of contracting heart disease is half that of a continuing smoker. The health risks of smoking are not uniform across all smokers. Risks vary according to amount of tobacco smoked, with those who smoke more at greater risk. Light smoking is still a health risk. Likewise, smoking "light" cigarettes does not reduce the risks.

The data regarding smoking to date focuses primarily on cigarette smoking, which increases mortality rates by 40% in those who smoke less than 10 cigarettes a day, by 70% in those who smoke 10–19 a day, by 90% in those who smoke 20–39 a day, and by 120% in those smoking two packs a day or more. Pipe smoking has also been researched and found to increase the risk of various cancers by 33%.

Some studies suggests that hookah smoking is considered to be safer than other forms of smoking. However, water is not effective for removing all relevant toxins, e.g. the carcinogenic aromatic hydrocarbons are not water-soluble. Several negative health effects are linked to hookah smoking and studies indicate that it is likely to be more harmful than cigarettes, due in part to the volume of smoke inhaled. In addition to the cancer risk, there is some risk of infectious disease resulting from pipe sharing, and other risks associated with the common addition of other psychoactive drugs to the tobacco.

Diseases caused by tobacco smoking are significant hazards to public health. According to the Canadian Lung Association, tobacco kills between 40,000–45,000 Canadians per year, more than the total number of deaths from AIDS, traffic accidents, suicide, murder, fires and accidental poisoning. 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."


Another way of looking at smoking would be some unique physiological effects which have spin-off benefits.

Health benefits of smoking :

Studies suggest that smoking decreases appetite.but did not conclude that overweight people should smoke or that their health would improve by smoking.

Several types of "Smoker’s Paradoxes",(cases where smoking appears to have specific beneficial effects), have been observed; often the actual mechanism remains undetermined. Risk of ulcerative colitis has been frequently shown to be reduced by smokers on a dose-dependent basis; the effect is eliminated if the individual stops smoking. Smoking appears to interfere with development of Kaposi's sarcoma, breast cancer among women carrying the very high risk BRCA gene,[citation needed] preeclampsia, and atopic disorders such as allergic asthma. A plausible mechanism of action in these cases may be the nicotine in tobacco smoke acting as an
anti-inflammatory agent and interfering with the disease process.

Evidence suggests that non-smokers are up to twice as likely as smokers to develop Parkinson's disease or Alzheimer's disease. A plausible explanation for these cases may be the effect of nicotine, a cholinergic stimulant, decreasing the levels of acetylcholine in the smoker's brain; Parkinson's disease occurs when the effect of dopamine is less than that of acetylcholine. In addition, nicotine stimulates the mesolimbic dopamine pathway (as do other drugs of abuse), causing an effective increase in dopamine levels. Opponents counter by noting that consumption of pure nicotine may be as beneficial as smoking without the risks associated with smoking
(as in CO poisoning).

Considering the high rates of physical sickness and deaths among persons suffering from schizophrenia, one of smoking's short term benefits is its temporary effect to improve alertness and cognitive functioning in that disease. It has been postulated that the mechanism of this effect is that schizophrenics have a disturbance of nicotinic receptor functioning. Rates of smoking have been found to be much higher in schizophrenics.