Several types of "Smoker’s Paradoxes",[1] (cases where smoking appears to have specific beneficial effects), have been observed. These effects should not be confused with altered mortality rate in "quitting ill". Patients who quit smoking have a temporary increase in mortality from lung cancer compared to smokers, but this is due to the rate of quitting smoking after receiving the diagnosis of lun
g cancer itself.[2][3]
[edit]Mechanism
Often the actual mechanism remains undetermined. A plausible mechanism of action in some cases may be the nicotine in tobacco smoke acting as an anti-inflammatory agent and interfering with the disease process.[4]
[edit]Specific conditions
Digestive system
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.[5][6]
Smokers are less often affected by aphthous ulcer.[7]
Cardiovascular system
Kaposi's sarcoma[8]
Reproductive/breasts
breast cancer among women carrying the very high risk BRCA gene[9]
Pre-eclampsia[10]
Smoking can also reduce rates of uterine fibroids.[11][12] This may be due to estrogen inhibition, as opposed to general inhibition of inflammation. The risk of endometriosis has been reported to be reduced in smokers.[13]
General
atopic disorders such as allergic asthma[14]
Neurologic
Smoking has been consistently found to be a protective factor on epidemiological studies for Parkinson's disease. The basis for such effect is not known but possibilities include an effect of nicotine as dopamine stimulant.[15]
The majority (80% in Australia as of 2001, 85% in the US as of 2007) of schizophrenics smoke, apparently to self-medicate.[16] Nicotine appears to be an effective antipsychotic, and work is underway to develop antipsychotic drugs based on nicotine without the ill effects of smoking or of nicotine itself.[17]
