Studies Show Harmful Impacts of Smoking Marijuana

June 23, 2009

A few days ago, the State of California Office of Environmental Health Hazard Assessment declared that marijuana smoke causes cancer. This was after an extensive review of over 30 scientific papers and a hearing. The state agency found marijuana smoke contains 33 of the same harmful chemicals as tobacco smoke.

Smoking marijuana is not medicine. It will make sick people sicker and healthy people sick. It may cause Kaposi’s sarcoma in people with AIDS (see below link to a study from Harvard Medical School). This is a fatal form of cancer. This is not compassionate.

No FDA approved medicines are smoked. It is difficult to administer safe, regulated dosages of medicines in smoked form. Furthermore, the harmful chemicals and carcinogens that are byproducts of smoking create entirely new health problems. [FN1]

Internet links to studies are below.

The respiratory difficulties associated with marijuana use preclude the inhaled route of administration as a medicine. Smoked marijuana is associated with higher concentrations of tar, carbon monoxide, and carcinogens than even cigarette smoke.[FN2]

Marijuana adversely impairs some aspects of lung function, causes abnormalities in the cells lining the airways of the upper and lower respiratory tract and in the airspaces deep within the lung, and it causes cancer.[FN3].

In addition to these cellular abnormalities and consequences, contaminants of marijuana smoke are known to include certain forms of bacteria and fungi. Those at particular risk for the development of disease and infection when these substances are inhaled, are those users with impaired immunity such as those with AIDS. [FN4]

Smoking marijuana can cause intoxication, precipitation of anxiety or acute psychotic reactions, orthostatic hypotension and bronchial inflammation. For a drug to be acceptable, its beneficial results must outweigh the adverse effects, especially when the claim is that it can be used repeatedly for symptomatic relief of chronic disorders.[FN5]

In recent years there has been a great public effort to curtail tobacco because of its effects on health yet the advocates of legalization promote smoking marijuana. Yet, a recent study shows that marijuana smoke has ammonia levels 20 times higher than tobacco smoke. Marijuana has hydrogen cyanide, nitric oxide, and aromatic amines at 3-5 times higher than tobacco smoke. [FN6]

Another study shows that that marijuana smokers face rapid lung destruction – as much as 20 years ahead of tobacco smokers. [FN7]

A just released study shows that marijuana damages DNA and that it is toxic to the body. [FN8]



[FN1] Brief of the Institute on Global Drug Policy of the Drug Free America Foundation; National Families in Action; Drug Watch International; Drug-free Kids: America’s Challenge, et al., as Amici Curiae in Support of Petitioner 2001WL 30659 (Jan. 10, 2001), U.S. v. Oakland Cannabis Buyers’ Cooperative, 121 S.Ct. 1711 (2001)

[FN2] Wu et al., Pulmonary hazards of smoking marijuana as compared with tobacco, NEJM, 1988:318:347-351.

[FN3] Barbers et al., Differential examination of bronchoalveolar lavage ceus in tobacco cigarette and marijuana smokers, Am Rev Respir Dis 1987:135:1271-1275; Fligiel et al., Bronchial pathology in chronic marijuana smokers: a light and electron microscopic study, Journal of Psychoactive Drugs 1988:20:33-42; Gong et al., Acute and subacute bronchial effects of oral cannabinoids, Clin Pharmacol There. 1984:35:26-32; Tashkin, Is frequent marijuana smoking harmful to health? Western Journal of Medicine 1993:158:635-637; Tashkin et al., Respiratory status of seventy-four habitual marijuana smokers, Chest 1980:78:699-706; Tashkin, Shapiro, Lee & Harper, Subacute effects of heavy marijuana smoking on pulmonary function in healthy men, NEJM 1976:294:125-129; Tashkin, Sirons & Clark, Effect of habitual smoking of marijuana alone and with tobacco on nonspecific airways hyperreactivity, Journal of Psychoactive Drugs 1988:20:21-25; Tilles et al., Marijuana smoking as cause of reduction in single-breath carbon monoxide diffusing capacity, American Journal of Medicine 1986:80:601-606; Barbers et al., Chemotaxis of peripheral blood and lung leukocytes obtained from tobacco and marijuana smokers, Journal of Psychoactive Drugs 1988:20:15-20; Bucklev, A case-control study of acute non-lvmphoblastic leukemia: evidence for an association with marijuana exposure, Cannabis: Physiopathology, Epidemiology, Detection pp. 155-162 (CRC Press 1993); Murison et al., Cannabinoids induce incomplete maturation of cultured human leukemia cells, Proc Natl Acad Sci USA 1987:84:5414-5418. Robison et al., Maternal drug use and risk of childhood non-lymphoblastic leukemia among offspring, Cancer 1989:63:1904-1911.

[FN4] Fleisher, Winawer & Zauber, Aspergillosis and marijuana, Annals of Internal Medicine 1991:115:578-579; Ramirez, Acute pulmonary histoplasmosis: newly recognized hazard of marijuana plant hunters, American Journal of Medicine 1990:88:5-60N-5-62N; Taylor et al., Salmonellosis associated with marijuana: a multi state outbreak traced by plasmid fingerprinting, NEJM 1982:306:1249-1254.

[FN5] “Smoked Marijuana as Medicine: Not Much Future,” Clinical Pharmacology & Therapeutics (2008), H Kalant, Department of Pharmacology, University of Toronto, Toronto, Ontario, Canada

[FN6] Marijuana Smoke Contains Higher Levels of Certain Toxins Than Tobacco Smoke, Science Daily, December 18, 2007

[FN7] Marijuana Smokers Face Rapid Lung Destruction – As Much as 20 Years Ahead of Tobacco Smokers, Science Daily, January 27, 2008

[FN8] Marijuana Damages DNA and May Cause Cancer, New Test Reveals, Science Daily, June 15, 2009

Additional new research on the link between marijuana and cancer


Marijuana Damages DNA And May Cause Cancer, New Test Reveals

Marijuana smoke may increase the risk of cancer, scientists report. (Credit: US Drug Enforcement Administration)

ScienceDaily (June 15, 2009) — Using a highly sensitive new test, scientists in Europe are reporting "convincing evidence" that marijuana smoke damages the genetic material DNA in ways that could increase the risk of cancer.

Researchers note that toxic substances in tobacco smoke can damage DNA and increase the risk of lung and other cancers. However, there has been uncertainty over whether marijuana smoke has the same effect. Scientists are especially concerned about the toxicity of acetaldehyde, present in both tobacco and marijuana. However, it has been difficult to measure DNA damage from acetaldehyde with conventional tests.

The research was carried out by Rajinder Singh, Jatinderpal Sandhu, Balvinder Kaur, Tina Juren, William P. Steward, Dan Segerback and Peter B. Farmer from the Cancer Biomarkers and Prevention Group, Department of Cancer Studies and Molecular Medicine and Karolinska Institute, Sweden.

Raj Singh said: “Parts of the plant Cannabis sativa, also known as marijuana, ganja, and various street names, are commonly smoked as a recreational drug, although its use for such purposes is illegal in many countries.

The scientists describe development and use of a modified mass spectrometry method that showed clear indications that marijuana smoke damages DNA.

“There have been many studies on the toxicity of tobacco smoke. It is known that tobacco smoke contains 4000 chemicals of which 60 are classed as carcinogens. Cannabis in contrast has not been so well studied. It is less combustible than tobacco and is often mixed with tobacco in use. Cannabis smoke contains 400 compounds including 60 cannabinoids. However, because of its lower combustibility it contains 50% more carcinogenic polycyclic aromatic hydrocarbons including naphthalene, benzanthracene, and benzopyrene, than tobacco smoke.”

The authors added: “It is well known that toxic substances in tobacco smoke can damage DNA and increase the risk of lung and other cancers. Scientists were unsure though whether cannabis smoke would have the same effect. Our research has focused on the toxicity of acetaldehyde, which is present in both tobacco and cannabis.”

The researchers add that the ability of cannabis smoke to damage DNA has significant human health implications especially as users tend to inhale more deeply than cigarette smokers, which increases respiratory burden. "The smoking of 3-4 cannabis cigarettes a day is associated with the same degree of damage to bronchial mucus membranes as 20 or more tobacco cigarettes a day," the team adds.

"In conclusion, these results provide evidence for the DNA damaging potential of cannabis [marijuana] smoke, implying that the consumption of cannabis cigarettes may be detrimental to human health with the possibility to initiate cancer development," the article states. "The data obtained from this study suggesting the DNA damaging potential of cannabis smoke highlight the need for stringent regulation of the consumption of cannabis cigarettes, thus limiting the development of adverse health effects such as cancer."


Journal reference:

1. Singh et al. Evaluation of the DNA Damaging Potential of Cannabis Cigarette Smoke by the Determination of Acetaldehyde Derived N2-Ethyl-2′-deoxyguanosine Adducts. Chemical Research in Toxicology, 2009; 22 (6): 1181 DOI: 10.1021/tx900106y

Adapted from materials provided by American Chemical Society.