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Why Marijuana Smoke Harm Reduction?
From the Newsletter of the Multidisciplinary Association for Psychedelic Studies
MAPS - Volume 6 Number 3 Summer 1996
Dale Gieringer, Ph.D. The waterpipe study was undertaken as a first step
toward marijuana harm reduction. It was motivated by concerns that, like
tobacco, marijuana smoking poses hazards to respiratory health, such as
increased risks of bronchitis, lung infection, and throat and neck cancers.
These hazards are not caused by the psychoactive ingredients in marijuana,
but by noxious vapors and solid particles, or tars, in the smoke produced by
leaf combustion. In practice, these hazards can be eliminated by oral
ingestion. However, smoking remains the most popular mode of consumption on
account of its faster action, greater convenience, and easier adjustability
of dosage.
Surveys indicate that some two or three million Americans are daily
marijuana smokers. Thousands of other Americans are currently smoking
marijuana for medical purposes in the treatment of cancer, AIDS, glaucoma,
and chronic pain and spasticity. To the extent that their health is already
compromised, such patients may be especially vulnerable to respiratory
infections caused by marijuana smoking.
There accordingly appears to be a need for technology to reduce the
respiratory hazards of marijuana. The most obvious fix is some form of smoke
filtration device to reduce, suppress, or otherwise separate noxious
by-products from the cannabinoids in the smokestream. Among the vast variety
of pipes, bongs, chillums, hookahs and other marijuana smoking devices
available, three basic technologies are in use: water filtration, cigarette
filters and vaporizers. The first two of these have been shown to be of some
value for tobacco. However, there has been virtually no published research
on any devices when used with marijuana. We accordingly undertook the
present study to find out which if any currently available technologies were
effective, and which offered most promise for further development. Our
research was guided by the philosophy of harm reduction, a concept
popularized by advocates of needle exchange, methadone maintenance, and
similar drug treatment measures. Harm reductionists hold that drug use is to
some degree inevitable, so it is better to mitigate the harmfulness of drugs
than to aggravate it through harsh and futile law
enforcement efforts. So far, harm reductionists have focused on hard drugs,
the major source of drug abuse problems. However, there is no reason harm
reduction efforts should not also be applied to marijuana.
Guiding Philosophy
Unfortunately, research in marijuana harm reduction has been stifled by
prohibitionist policymakers, who mistrust efforts to mitigate the adverse
effects of drugs on the grounds they make illicit drug use acceptable. Not
surprisingly, it proved impossible for us to interest the National Institute
on Drug Abuse in supporting our project. They reminded us that the tobacco
industry had spent billions developing a smokeless cigarette, only to
withdraw it in the face of consumer distaste and active hostility from the
anti-tobacco lobby. Sadly, the reduction of smoking-related harm is viewed
as a threat by many anti-drug zealots, insofar as it undermines their
rationale for prohibiting drugs in the
first place. Thus the anti-drug lobby has actively impeded the development
of marijuana harm reduction technology by lobbying for anti-paraphernalia
laws, which outlaw the manufacture of devices for smoking controlled substances.
Adverse Effects
Harm reduction has equally little appeal to those marijuana enthusiasts who
naively believe that marijuana, alone of all drugs, is a perfectly harmless
herb. This delusion is quickly refuted by a review of the medical
literature, which reveals extensive evidence of possible adverse effects of
marijuana. From a physiological standpoint, these effects are mostly mild or
of marginal significance, such as temporarily elevated heartbeat, slight and
subtle impacts on immune cells, alleged changes in endocrine functioning;
disputed and marginal influences on newborns, and so forth.
Of considerably
more consequence are the alleged psychological effects, including increased
risk of accidents, impaired school and job performance, amotivation,
heightened risk of drug abuse and sundry other social pathologies.
Nevertheless, from the standpoint of physical health, the single best
established hazard of marijuana use appears to be an increased risk of lung
disease from smoking. According to Dr. Lester Grinspoon, "After carefully
monitoring the literature for more than two decades, we have concluded that
the only well- confirmed deleterious physical effect of marihuana is harm to
the pulmonary system."1
This should come as no surprise to any naive
non-smoker who has exploded in a paroxysm of coughing after inhaling his or
her first toke of marijuana. Chemically, marijuana and tobacco smoke are
quite similar, aside from their psychoactive ingredients: both arise from
the combustion of leafy material, which produces a host of noxious gases and
solid particulates, or tars,
that are known to be hazardous to respiratory health.2
Dating back to the
British Indian Hemp Drugs Commission a century ago, observers have noted a
high rate of bronchitis and other respiratory diseases among chronic ganja
smokers in India, Jamaica and elsewhere;3 however, interpretation of the
data has been clouded by the subjects' high rate of tobacco use, making it
impossible to determine whether cannabis itself was responsible. This issue
has been resolved thanks to modern clinical research by Dr. Donald Tashkin
at UCLA, who has followed separate
cohorts of marijuana-only, tobacco-only, marijuana-and-tobacco, and
non-smoking subjects. Dr. Tashkin's work indicates that heavy daily
marijuana smokers are more susceptible than non-marijuana smokers to
respiratory disorders such as coughing, bronchitis, impaired lung immune
function, and potentially precancerous cell changes.4
Epidemiological Research
In the last couple of years, there has also emerged epidemiological evidence
of marijuana's respiratory hazards. A prospective study of 902 subjects by
the Kaiser Permanente Center found that daily marijuana-only smokers had a
19% higher rate of respiratory complaints than non-smokers.5 They also found
a 30% higher rate of injuries, perhaps reflecting an increased risk of
accidents.
Surprisingly, those subjects who had used marijuana for the longest time
(>15 years) showed no increase in respiratory illness but a higher risk of
injuries, while those who had used marijuana for less than 15 years suffered
more respiratory complaints, but not injuries! The Kaiser study was not
large enough to detect changes in mortality, but a larger study is in progress.
In the meantime, an important, unsettled concern is that of lung cancer.
Despite the fact that epidemiosmoking increases the risk of cancer,
especially in the throat and upper respiratory tract.6 To begin with, the
tars from marijuana contain most of the same carcinogens as tobacco, to a
greater or lesser extent.7 It has been argued that marijuana is even more
carcinogenic than tobacco because it contains some 50% more of the highly
potent carcinogens known as polycyclic aromatic hydrocarbons, by-products of
incomplete combustion which are thought to be a prime culprit in lung
cancer. In reply, hempsters contend that tobacco is more dangerous because
it contains far more radioactive carcinogens, particularly polonium-210.8
However, this point seems moot in the light of experiments by the
Leuchtenbergers and others, showing that marijuana tars, like those of
tobacco, produce carcinogenic changes when applied to both animal and human
lung tissue cultures.9
The most compelling evidence of marijuana's potential carcinogenicity comes
from recent clinical reports of throat and neck cancer in young
marijuana-using males. This was first discovered by oncologist Dr. Paul
Donald at the University of California at Davis, who in examining six
patients who had contracted throat and neck cancer at the unusually early
age of under 40, found that every one had a history of marijuana use.10
Although most of the patients also had other risk factors such as tobacco
smoking or heavy drinking, marijuana use was the only one common to them
all. Subsequent investigations by Dr. Donald and other oncologists have
continued to find suspiciously high rates of marijuana use among younger
throat, neck and tongue cancer patients, suggesting the possibility of a
significant upsurge in upper respiratory tract cancers in coming years as
the sixties generation ages.11 The link between marijuana and throat cancer
seems especially compelling in light of Dr. Tashkin's work, which indicates
that cannabis smoke tends to concentrate in the larger, upper passages of
the respiratory tract.12 In contrast, cigarette smoke is more likely to
penetrate to
the smaller, lower air passageways, where most tobacco-related lung cancers
originate. It is still unclear whether marijuana plays a significant role in
cancer of the lower lungs. However, Dr. Tashkin warns that the total tissue
area in the upper respiratory passages is much smaller than that in the
lower passages, so that marijuana smokers may well be exposing their throats
to a
proportionately much greater concentration of carcinogens. It is therefore
possible that marijuana is a greater risk to the throat than cigarettes to
the lungs. On the other hand, marijuana appears to be a much lesser factor
in emphysema, which originates in the lower lungs.
Marijuana Smoke vs. Tobacco Smoke
It is tempting to try to compare marijuana and cigarette smoking. An exact
comparison is hard to make, given that marijuana and tobacco affect
different parts of the respiratory system differently.
Anti-marijuana propagandists like to say that one joint per day is
equivalent to one pack a day of cigarettes. This myth misrepresents a study
by Dr. Tashkin, which found that one-joint-per-day marijuana smokers
experienced a "mild but significant" increase in airflow resistance in the
large airways greater than that seen in persons smoking 16 cigarettes today.
However, the same study
found that marijuana smokers did much better in other measures of
respiratory health. A more accurate comparison based on studies by Dr.
Tashkin's group is that marijuana smokers absorb four times as much tar in
their lungs than cigarette smokers per weight smoked.13 Given that a typical
joint weighs about .4 - .5 grams, one-half as much as a tobacco cigarette, a
rough equivalence is 2 cigarettes = 1 joint. With this information in mind,
we undertook to explore various ways of filtering marijuana smoke.
Waterpipes were the most obvious candidate, being widely available in head
shops and popular with many users on account of the apparent mildness of
their smoke. We were especially encouraged by research showing that
waterpipes could be highly effective in filtering tobacco;14 unfortunately,
we were to discover that these results did not hold up
for marijuana.
A second candidate technology that would likewise prove
disappointing was cigarette filters, which are widely available and can be
easily adapted to marijuana by means of a simple homemade filter holder. We
did not consider the more advanced "smokeless cigarette" developed by RJ
Reynolds, due to the fact that it is not actually a smoke filtration device,
but rather an inhaler for artificially flavored nicotine, which is of no use
for marijuana.
Instead, we turned our attention to vaporizers, which have
been touted as a possible ideal solution to the cannabis smoking problem.
Unfortunately, because vaporizers can't be used with tobacco, they are
prohibited under US paraphernalia laws, and users must accordingly resort to
homemade designs. We obtained one such device from the San Francisco
Cannabis Buyers Club. Another was obtained from a Canadian supplier, who is
selling them on that country's newly emerged, illegal but tolerated "gray
market" in Vancouver. Although neither device performed close to the
smokeless ideal, our study left reasonable hope that substantial improvement
is possible. Given the evident need to reduce the health risks of marijuana
smoking, vaporization merits further research and development.
References
Lester Grinspoon & James Bakalar, Marihuana: The Forbidden Medicine
(Yale University,1993), pp.151-2. One important issue that has not been
settled is whether there are significant differences in chemistry between
the government-supplied marijuana leaf used in laboratory studies and the
sinsemilla bud that has become popular in recent decades.
Helen C Jones & Paul Lovinger, The Marijuana Question (Dodd Mead & Co.,
New York 1985), pp. 16-21.
Donald Tashkin et al., "Effects of Habitual Use of Marijuana and/or
Cocaine on the Lung," in Research Findings on Smoking of Abused
Substances, NIDA Research Monograph 99 (1990).
Michael R Polen et al., "Health Care Use by Frequent Marijuana Smokers
Who Do Not Smoke Tobacco," Western Journal of Medicine 158 #6: 596-601
(June 1993). Donald Tashkin, "Is Frequent Marijuana Smoking
Hazardous To Health?" Western Journal of Medicine 158 #6: 635-7 (June 1993).
National Academy of Sciences, "Marijuana and Health," (Report by a
Committee of the Institute of Medicine, National Academy Press 1982),
pp. 14-7.
Jack Herer, The Emperor Wears No Clothes, 1991 Edition, pp. 81, 114-5.
"The difference in radioactivity between cannabis and tobacco may have
less to do with plant genetics than with differences in the soil and
fertilizer used for the two crops."
Cecile and Rudolf Leuchtenberger, "Cytological and cytochemical studies
of the effects of fresh marihuana cigarette smoke on growth and DNA
metabolism of animal and human lung cultures," in MC Braude and S
Szara, ed: The Pharmacology of Marihuana (Raven Press, New York
1976).
Paul Donald, "Marijuana smoking - Possible cause of head and neck
carcinoma in young patients," Otolaryngology - Head and Neck Surgery;
Vol 94: 517-21 (April 1986).
Frank M Taylor, "Marijuana as a potential respiratory tract carcinogen:
A retrospective analysis of a community hospital population,"
Southern Medical Journal 81:1231-6 (1988);
Gideon Caplan and Brian Brigham, "Marijuana smoking and carcinoma of
the tongue: Is there an association?" Cancer 66:1005-6 (1990); PJ
Donald, "Advanced malignancy in the young marijuana smoker,"
Advances in Experimental Medicine and Biology, 288: 33-56 (1991).
Donald Tashkin et al., "Effects of Habitual Use of Marijuana and/or
Cocaine on the Lung," loc. cit.
T-C Wu, DP Tashkin, B Djahed and JE Rose, "Pulmonary hazards of smoking
marijuana as compared with tobacco," New England Journal of Medicine 318:
347-51 (1988).
D Hoffmann, G Rathkamp and E Wynder, "Comparison of the yields of
several selected components in the smoke from different tobacco
products," Journal of the National Cancer Institute 31#1-6: 627-35
(Jul-Dec 1963).
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