Although the use of cannabis is not harmless, its link with death is still not established, argues senior researcher, Dr. Steve Sidney, Kaiser Permanente, Northern California, Division of Research in this week's BMJ. (9.19.03)
Two large studies reported no increase in death associated with the use of cannabis. Even diseases that might be related to long term cannabis use are unlikely to have a sizeable public health impact because, unlike users of tobacco and alcohol, most people who try cannabis quit relatively early in their adult lives, writes the author.
Exposure to smoke is also generally much lower in cannabis than in tobacco cigarette smokers, even taking into account the larger exposure per puff, while several. Existing studies do not support a link between the use of cannabis and heart disease, the leading cause of death in many Western countries. Cannabis does not contain nicotine, a chemical contained in tobacco that is addicting and contributes importantly to the risk of heart disease.
However, two caveats must be noted regarding available data, warns the author. Firstly, the studies to date have not followed cannabis smokers into later adult life so it might be too early to detect an increase risk of chronic diseases that are potentially associated with the use of cannabis.
Secondly, the low rate of regular cannabis use and the high rate of discontinuation during young adulthood may reflect the illegality and social disapproval of the use of cannabis. This means that we cannot assume that smoking cannabis would continue to have the same small impact on mortality if its use were to be decriminalized or legalized.
While the use of cannabis is not harmless, our current knowledge does not support the assertion that is has an adverse impact on death rates. Common sense should dictate measures to minimize adverse effects, says the author. These include discouraging use by teenagers, not using when driving or operating heavy machinery, not using excessively, and cautioning people with known coronary heart disease.
S. Sidney, Comparing cannabis with tobacco--again. BMJ. 2003 Sep 20;327(7416):635-6.