Study: Cannabis Smoking Not Associated With Increased Lung Cancer Risk Or Other Serious Pulmonary ComplicationsJune 19, 2013
A forthcoming review to be published in journal Annals of the American Thoracic Society reiterates that the ingestion of cannabis smoke poses nominal pulmonary risks compared to those associated with tobacco smoke. The author of the paper, Donald P. Tashkin, MD, emeritus professor of medicine and medical director of the Pulmonary Function Laboratory at the David Geffen School of Medicine at University of California, Los Angeles performed US-government sponsored studies of marijuana and lung function for over 30 years.
A preview of Dr. Tashkin’s forthcoming review appears on the American Thoracic Society news website here. It reads:
Dr. Tashkin found that regular smoking of marijuana by itself causes visible and microscopic injury to the large airways that is consistently associated with an increased likelihood of symptoms of chronic bronchitis that subside after cessation of use. He also found that the evidence does not indicate that habitual use of marijuana leads to significant abnormalities in lung function when assessed either cross-sectionally or longitudinally, except for possible increases in lung volumes and modest increases in airway resistance of unclear clinical significance.
The author finds no clear link between marijuana use and the development of COPD or lower respiratory tract infections. In addition, “findings from a limited number of well-designed epidemiological studies do not suggest an increased risk for the development of either lung or upper airway cancer from light or moderate use, although evidence is mixed concerning possible carcinogenic risks of heavy, long-term use,” Dr. Tashkin notes. “In summary, the accumulated weight of evidence implies far lower risks for pulmonary complications of even regular heavy use of marijuana compared to the grave pulmonary consequences of tobacco.”
The full paper will be available later this month.
In May, presenters at the annual meeting of the American Academy for Cancer Research reported that subjects who regularly inhale cannabis smoke possess no greater risk of lung cancer than do those who consume it occasionally or not at all — according to an analysis of six case-control studies, conducted between 1999 and 2012, involving over 5,000 subjects (2,159 cases and 2,985 controls) from around the world.
Last year, clinical data published in the Journal of the American Medical Association (JAMA) reported that subjects’ exposure to moderate levels of cannabis smoke, even over the long-term, is not associated with significant adverse effects on pulmonary function.
Vaporizers, which heat marijuana to a point where cannabinoid vapors form, but below the point of combustion, reduce subjects’ intake of potentially hazardous combustible compounds. In several clinical trials, investigators have concluded that vaporization is a “safe and effective” cannabinoid delivery mode that “does not result in exposure to combustion gases.” Researchers also report that vaporization results in higher plasma concentrations of THC compared to smoked cannabis.
The amended bill calls for the creation of four state-sanctioned marijuana dispensing facilities to produce and distribute cannabis to state-qualified patients who possess a physician’s recommendation. Patients diagnosed with one of approximately twenty qualifying conditions — including cancer, hepatitis C, amyotrophic lateral sclerosis, muscular dystrophy, Crohn’s disease, or multiple sclerosis — would be permitted to legally possess up to than two-ounces of cannabis. Under the proposed law, patients must obtain cannabis only from a state-licensed facility. Qualified patients will not be provided with any legal protections to possess or use cannabis prior to the establishment of such facilities.
As originally passed by the House, the measure allowed for qualified patients to have the option to grow their own cannabis. The measure also allowed for physicians to recommend cannabis for the treatment of post-traumatic stress. Both provisions were stripped from the bill by the Senate at the request of newly-elected Democrat Gov. Maggie Hassan.
Gov. Hassan is expected to approve the reconciled version of HB 573. A commission is expected to be put in place to oversee the implementation of the law as soon as the bill is passed.
New Hampshire will become the 19th state to allow for the limited, legal use of medical cannabis and the final New England state to do so.
Daylin Leach has been an outspoken advocate on the issue of marijuana law reform during his tenure in Harrisburg. Senator Leach made a splash legislatively this year when he introduced Senate Bill 528, which would legalize and regulate the adult use of marijuana in Pennsylvania, the first time such a bill was introduced in the state.
Senator Leach was also featured as the keynote speaker at the first ever NORML Mid-Atlantic Conference which was held this March in Philadelphia, Pennsylvania. You can view video of his remarks here.
State Senator Leach is now looking to take his advocacy to Capitol Hill. He is running for an open seat representing Pennsylvania’s 13th Congressional District in the United States House of Representatives that will be vacated by Congresswoman Alison Schwartz, who is stepping down from her post to pursue the governorship in 2014. While the Democratic Primary for this position won’t be held until May of next year, Senator Leach’s campaign is already kicking into full gear and he is emerging as an early favorite in the race. In a statement released to NORML, Senator Leach has made clear that he intends to continue his fight for marijuana legalization while serving at the federal level:
“We have spent billions of dollars nationally investigating, prosecuting, incarcerating, and monitoring millions of our fellow citizens who have hurt no one, damaged no property, breached no peace. In 15 years marijuana prohibition will be some quaint thing of the past that will be the subject of exhibitions at the Constitution Center. People will think it’s crazy that it was ever illegal. As State Senator in Pennsylvania I introduced legislation to end this costly, failed policy of marijuana prohibition and replace it with a system of legalization and regulation. If elected to the United States House of Representatives I will continue to fight for rational marijuana policies at the national level and work to bring an end to this discriminatory, ineffective prohibition.” – Pennsylvania State Senator, and NORML PAC Supported US House Candidate, Daylin Leach
We need more passionate supporters like Senator Leach in Washington, DC. As public opinion swings further in the direction of full legalization everyday, we can only hope Senator Leach’s candidacy, and his potential future terms in the House of Representatives, inspires more of his colleagues to join him in the fight for reforming our country’s marijuana laws. With more federal elected officials who can speak as articulately about the problems of our failed prohibition and the benefits of moving to a legalized, regulated system as Senator Leach, we will see reforms occur at the federal level sooner rather than later.
Another study has once again affirmed that the enactment of statewide medical cannabis laws is not associated with increased rates of adolescent marijuana consumption.
According to data published this week in the American Journal of Public Health, the passage of medical marijuana laws in various states has had no “statistically significant … effect on the prevalence of either lifetime or 30-day marijuana use” by adolescents residing in those states.
Researchers at the University of Florida College of Medicine evaluated the effects of medical marijuana laws on adolescent marijuana use rates during the years 2003 and 2011. Investigators “found no evidence of intermediate-term effects of passage of state MMLs (medical marijuana laws) on the prevalence or frequency of adolescent nonmedical marijuana use in the states evaluated.” Authors concluded, “Our results suggest that, in the states assessed here, MMLs have not measurably affected adolescent marijuana use.”
The study’s findings rebut often repeated claims from cannabis prohibitionists that the passage of therapeutic cannabis laws adversely impacts teens’ usage of the substance.
In fact, numerous published studies have contradicted this claim. A 2012 analysis of statewide cannabis laws and adolescent use patterns of commissioned by the Institute for the Study of Labor (IZA) in Germany concluded: “Our results suggest that the legalization of medical marijuana was not accompanied by increases in the use of marijuana or other substances such as alcohol and cocaine among high school students. Interestingly, several of our estimates suggest that marijuana use actually declined with the passage of medical marijuana laws.”
A separate 2012 study by researchers at McGill University in Montreal and published in the journal Annals of Epidemiology reported similar findings, concluding: “[P]assing MMLs (medical marijuana laws) decreased past-month use among adolescents … and had no discernible effect on the perceived riskiness of monthly use. … [These] estimates suggest that reported adolescent marijuana use may actually decrease following the passing of medical marijuana laws.”
Previous investigations by research teams at Brown University in 2011 and Texas A&M in 2007 made similar determinations, concluding, “[C]onsistent with other studies of the liberalization of cannabis laws, medical cannabis laws do not appear to increase use of the drug.”
Full text of the study, “Effects of State Medical Marijuana Laws on Adolescent Marijuana Use,” appears online in the American Journal of Public Health.
It appears that Alaska is likely to be the next state to have the opportunity to vote on marijuana legalization. This week, the Lt. Governor’s office approved a ballot initiative that aims to tax and regulate marijuana in a manner similar to the laws recently approved in Colorado and Washington. If approved, the initiative would allow adults over the age of 21 to possess up to one ounce of marijuana and provide for the establishment of legal, regulated retail outlets and grow operations.
Supporters must now collect 30,169 signatures to place the initiative on the ballot, which they aim to complete by January.
NORML will keep you updated as this effort moves forward.