Lifespan of meth user: This article says 5 years but cites no sources.
http://substanceabuse.lifetips.com/cat/63346/meth-and-amphetamines/index.html
However, a PDF from the Pennsylvania Department of Health says that the average addict will live 5-10 years.
PDF can be found in third link
http://www.google.com/search?q=life...s=org.mozilla:en-US:official&client=firefox-a
Lifespan of a smoker:
Medical News Today states that a 30 year old smoker can expect to live about 35 more years where as a non smoker can expect to live 53 more years.
http://www.medicalnewstoday.com/articles/9703.php
Human lifespan:
The World Bank says in 2008 the average expected lifespan was around 78.5 years
http://www.google.com/search?q=aver...s=org.mozilla:en-US:official&client=firefox-a
The two previous articles have conflicting data for life expectancy, however they are relatively close. 78-83 years. The Medical News states a non smoker can expect to live to 83, the world bank does not say if they are including smokers in their figure or not.
Side-effects of Meth use:
Cardiovascular stress-common
Overheating-common
Sleep deprivation (days on end)- common for user
Oxidative damage to organs- common for user
Tooth rot- common for user
Neurotoxicity- frequency may lead to behavioral changes
Heart attack
Stroke
http://www.erowid.org/chemicals/amphetamines/amphetamines_health.shtml
(erowid)
...all sounds about similar to tobacco. However, according to the data meth users will die a good 20 years before a smoker.
Nicotine overdose is relatively impossible if administered by smoking
http://learn.genetics.utah.edu/content/addiction/drugs/overdose.html
(Univeristy of Utah)
Overdose of methamphetamine is extremely low, around 50 milligrams for a new user. Body chemistry makes it hard to determine a "safe" does.
http://www.erowid.org/chemicals/meth/meth_faq.shtml
(Erowid)
Meth overdose side-effects:
Dehydration, heart attack, stroke, kidney and other organ failures
http://www.montana.edu/wwwai/imsd/rezmeth/effmethod.htm
A smoker can expect to die a smoking related death (when at the age of 30) around the age of 65. A meth user can expect to die a meth related death within 10 years (assuming no overdose, which admittedly is unknown and presumably uncommon for an otherwise healthy individual). In the mean time, meth users are prone to withdrawal that ends in days of sleeping, depression, and psychotic reactions. Long term use can lead to amphetamine psychosis, which is similar to paranoid schizophrenia.
http://www.erowid.org/chemicals/meth/meth_effects.shtml
Conclusion: Both will kill you, meth will kill you faster. Meth addiction is not a functional one for a majority of users, unlike tobacco.