The inhalation of one marijuana cigarette per day over a 20-year period is not associated with adverse changes in lung health, according to data published online ahead of print in the journal Annals of the American Thoracic Society.
Investigators at Emory University in Atlanta assessed marijuana smoke exposure and lung health in a large representative sample of US adults age 18 to 59. Researchers reported that cannabis exposure was not associated with FEV1 (forced expiratory volume) decline or deleterious change in spirometric values of small airways disease.
Authors further reported that marijuana smoke exposure may even be associated with some protective lung effects among long-term smokers of tobacco. Investigators acknowledged, “[T]he pattern of marijuana’s effects seems to be distinctly different when compared to that of tobacco use.”
Researchers also acknowledged that habitual cannabis consumers were more likely to self-report increased symptoms of bronchitis, a finding that is consistent with previous literature. Separate studies indicate that subjects who vaporize cannabis report fewer adverse respiratory symptoms than do those who inhale combustive marijuana smoke.
Authors concluded, “[I]n a large representative sample of US adults, ongoing use of marijuana is associated with increased respiratory symptoms of bronchitis without a significant functional abnormality in spirometry, and cumulative marijuana use under 20 joint-years is not associated with significant effects on lung function.”
This study is the largest cross-sectional analysis to date examining the relationship between marijuana use and spirometric parameters of lung health.
A separate study published in 2012 in The Journal of the American Medical Association (JAMA) similarly reported that cumulative marijuana smoke exposure over a period of up to 7 joint-years (the equivalent of up to one marijuana cigarette per day for seven years) was not associated with adverse effects on pulmonary function.
A 2013 review also published in the Annals of the American Thoracic Society acknowledged that marijuana smoke exposure was not positively associated with the development of lung cancer, chronic obstructive pulmonary disease (COPD), emphysema, or bullous lung disease. It concluded: “[H]abitual use of marijuana alone does not appear to lead to significant abnormalities in lung function. Findings from a limited number of well-designed epidemiological studies do not suggest an increased risk of either lung or upper airway cancer from light or moderate use. … Overall, the risks of pulmonary complications of regular use of marijuana appear to be relatively small and far lower than those of tobacco smoking.”
You may view an abstract of the study, “Effects of marijuana exposure on expiratory airflow: A study of adults who participated in the US National Health and Nutrition Examination Study,” here.
NORML reviews the top news stories of 2014.
#1 Marijuana Legalization Measures Win Big On Election Day
Voters in Oregon and Alaska decided on Election Day in favor of statewide initiatives legalizing the commercial production and sale of marijuana for adults, while voters in the nation’s capitol and in numerous other cities nationwide similarly decided on local measures to eliminate marijuana possession penalties.
#2 Colorado And Washington Begin Regulating Retail Marijuana Sales
Two states, Colorado and Washington, initiated retail marijuana sales in 2014. Colorado’s program began on January 1. In Washington, state-licensed retail outlets began legally selling cannabis to adults in July.
#3 Congress Enacts Measure Protecting State-Sponsored Medi-Pot Programs
President Barack Obama signed spending legislation into law in December that included a provision limiting the Justice Department’s ability to take criminal action against state-licensed individuals or operations that are acting in full compliance with the medical marijuana laws of their states. The amendment states, “None of the funds made available in this act to the Department of Justice may be used … to prevent … states … from implementing their own state laws that authorize the use, distribution, possession, or cultivation of medical marijuana.”
#4 Congress Moves To Permit State-Sanctioned Hemp Cultivation
Federal lawmakers approved legislation in February permitting state-sponsored hemp cultivation to move forward despite the plant’s federal status as a Schedule I prohibited substance.
#5 Federal Judge Hears Challenge To Cannabis’ Schedule I Status
United States District Judge Kimberly Mueller heard five days of testimony in October in regard to the constitutionality of marijuana’s Schedule I status under federal law. Defense counsel and their experts argued that the scientific literature is not supportive of the plant’s present categorization. Judge Mueller is expected to make her ruling in early 2015.
#6 JAMA: Fewer Opiate-Related Deaths In Medical Marijuana States
The enactment of statewide medicinal marijuana laws is associated with significantly lower state-level opioid overdose mortality rates, according to data published in August in JAMA Internal Medicine. Researchers reported, “States with medical cannabis laws had a 24.8 percent lower mean annual opioid overdose mortality rate compared with states without medical cannabis laws.”
#7 President Acknowledges That Booze Is More Harmful Than Marijuana
Consuming cannabis is less harmful to the individual than is drinking alcohol, President Barack Obama acknowledged in January in an interview with The New Yorker. “I don’t think it (marijuana) is more dangerous than alcohol,” he stated. He added, [W]e should not be locking up kids or individual users for long stretches of jail time.”
#8 Study: Medical Marijuana States Have Fewer Violent Crimes
Medicinal cannabis laws are not associated with any rise in statewide criminal activity, according to data published in April in the journal PLoS ONE. “Medical marijuana laws were not found to have a crime exacerbating effect on any of the seven crime types. On the contrary, our findings indicated that MML precedes a reduction in homicide and assault,” authors concluded. “In sum, these findings run counter to arguments suggesting the legalization of marijuana for medical purposes poses a danger to public health in terms of exposure to violent crime and property crimes.”
#9 NYT Editors Opine In Favor Of Legalizing Cannabis
The New York Times editorial board in July called upon federal lawmakers to end the criminalization of cannabis for those over the age of 21. The paper’s editors opined: “The federal government should repeal the ban on marijuana. … Moderate use of marijuana does not appear to pose a risk for otherwise healthy adults. … [W]e believe that on every level, … the balance falls squarely on the side of national legalization.”
#10 Americans Say Marijuana Is Less Harmful To Health Than Sugar
Americans believe that consuming cannabis poses less harm to health than does the consumption of tobacco, alcohol, or sugar, according to the findings of a Wall Street Journal/NBC News poll released in March. Respondents were asked which of the four substances they believed to be “most harmful to a person’s overall health.” Most respondents said tobacco (49 percent), followed by alcohol (24 percent) and sugar (15 percent).
State Public Health Department officials have recommended over $7 million dollars in grant funding to pay for a series of state-sponsored clinical trials to assess the safety and efficacy of cannabis and cannabinoids.
The proposed studies include a pair of clinical trials to evaluate the use of cannabidiol (CBD), a nonpsychotropic plant cannabinoid, for patients with pediatric epilepsy. Two additional trials will assess the use of cannabis for patients suffering from post-traumatic stress. Other studies will assess the efficacy of either cannabis or CBD in the treatment of Parkinson’s disease, brain tumors, ulcerative colitis, and pain management. (More specific summaries of all eight proposed studies are available online here.)
Grant funding for the proposed studies requires final approval by the state Board of Health in December.
Following funding approval, researchers will still be required to gain additional federal approval in order to obtain access to research-grade cannabis or CBD.
The state of California previously sponsored a similar series of clinical trials assessing the safety and efficacy of marijuana. Those studies evaluated the use of whole-plant cannabis in patients with neuropathy, multiple sclerosis, and autoimmune deficiencies. A summary of those trials, published in 2012, concluded, “Based on evidence currently available the Schedule I classification is not tenable; it is not accurate that cannabis has no medical value, or that information on safety is lacking.”
[excerpt] A new study identifying minor differences in the brain imaging of habitual marijuana consumers compared to non-users may be ideal for stimulating sensational headlines (e.g., “Regular pot smokers have shrunken brains, study says,” Los Angeles Times, November 10), but tells us little in regard to whether pot poses actual health risks.
Specifically, an MRI scan revealed less gray matter in the orbital frontal cortex of pot-smoking subjects compared to those who had never used the drug. Researchers also identified increased connectivity between certain regions of the brain in regular marijuana users compared with non-users.
So precisely what do these findings tell us in regard to pot use and health? Not much. Since the study design is not longitudinal, investigators cannot determine whether these differences are caused by subject’s cannabis use, whether these differences existed prior to subjects’ ever trying cannabis, or whether these differences persist when users’ cannabis consumption ceases.
Most importantly, investigators in this study failed to determine whether any of these differences are positively associated with any measurable adverse performance outcomes, such as cognitive performance or quality of life. It may be that these cannabis users are functioning in their daily lives in a manner that is indistinguishable from controls, in which case the imaging differences may hold little if any real-world significance. (In fact, one of the paper’s authors acknowledged, “[C]hronic users appear to be doing fine.”)
Full text of NORML’s response, “Media Leaping to Extremely Faulty Conclusions from Study on the Effects of Marijuana on the Brain,” appears online here.
Moderate cannabis consumption by young people is not positively associated with changes in intelligence quotient (IQ), according to data presented this week at the European College of Neuropsychopharmacology annual congress in Berlin, Germany.
Investigators at the University College of London analyzed data from 2,612 subjects who had their IQ tested at the age of eight and again at age 15. They reported no relationship between cannabis use and lower IQ at age 15 when confounding factors such as subjects’ history of alcohol use and cigarette use were taken into account.
“In particular alcohol use was found to be strongly associated with IQ decline,” the authors wrote in a press release cited by The Washington Post. “No other factors were found to be predictive of IQ change.”
Quoted in the Independent Business Times, the study’s lead author said: “Our findings suggest cannabis may not have a detrimental effect on cognition, once we account for other related factors particularly cigarette and alcohol use. This may suggest that previous research findings showing poorer cognitive performance in cannabis users may have resulted from the lifestyle, behavior and personal history typically associated with cannabis use, rather than cannabis use itself.”
The investigators acknowledged that more chronic marijuana use, defined in the study as a subject’s admission of having consumed cannabis 50 times or more by age 15, was correlated with slightly poorer exam results at the age of 16 — even after controlling for other variables. However, investigators admitted: “It’s hard to know what causes what. Do kids do badly at school because they are smoking weed, or do they smoke weed because they’re doing badly?”
Commenting on the newly presented data, the meeting’s Chair, Guy Goodwin, from the University of Oxford, told BBC News: “This is a potentially important study because it suggests that the current focus on the alleged harms of cannabis may be obscuring the fact that its use is often correlated with that of other even more freely available drugs and possibly lifestyle factors.”
In a recent review published in the New England Journal of Medicine, the NIDA Director Nora Volkow alleged that cannabis use, particularly by adolescents, is associated with brain alterations and lower IQ. However, the IQ study cited by Ms. Volkow as the basis of her claim was later questioned in a separate analysis published in the Proceedings of the National Academy of Sciences. That paper suggested that socioeconomics, not subjects’ cannabis use, was responsible for differences in IQ and that the plant’s “true effect [on intelligence quotient] could be zero.”
A previous assessment of cannabis use and its potential impact on intelligence quotient in a cohort of young people tracked since birth reported, “[M]arijuana does not have a long-term negative impact on global intelligence.”