Drivers who test positive for the presence of THC in blood are no more likely to be involved in motor vehicle crashes than are drug-free drivers, according to a federally sponsored case-control study involving some 9,000 participants. The study, published Friday by the United States National Highway Traffic Administration (NHTSA), is the first large-scale case-control study ever conducted in the United States to assess the crash risk associated with both drugs and alcohol use by drivers.
Authors reported that drivers who tested positive for any amount of THC possessed an unadjusted, elevated risk of accident of 25 percent (Odds Ratio=1.25) compared to controls (drivers who tested negative for any drug or alcohol). However, this elevated risk became insignificant (OR=1.05) after investigators adjusted for demographic variables, such as the drivers’ age and gender. After researchers controlled for both demographic variables and the presence of alcohol, THC-positive drivers’ elevated risk of accident was zero (OR=1).
By contrast, researchers reported that drivers who tested positive for low levels of alcohol possessed a statistically significant risk of accident, even after controlling for demographic variables (e.g., Drivers with a BAC of 0.03 possessed a 20 percent greater risk of motor vehicle accident [OR=1.20] compared to controls). Drivers with BAC levels of 0.05 possessed a greater than two-fold risk of accident (OR=2.07) while motorists with BAC levels of 0.08 possessed a nearly four-fold risk of accident (OR=3.93).
Researchers did not analyze drivers’ THC levels to similarly estimate whether higher or lower THC levels may impact crash risk in a dose-dependent manner, as has been previously reported in some separate analyses of fatal crash data.
Authors concluded, “This finding indicates that these other variables (age, gender, ethnicity, and alcohol use) were highly correlated with drug use and account for much of the increased (crash) risk associated with the use of illegal drugs and THC.”
The study’s finding contradict allegations by NIDA and others that “marijuana use more than doubles a driver’s risk of being in an accident,” but are largely consistent with those of a 2013 literature review published in the journal Accident Analysis and Prevention which reported that cannabis-positive drivers did not possess a statistically significant risk of a either fatal accident or a motor vehicle accident causing injury.
See NORML’s white paper on cannabis and psychomotor performance here.
Newly appointed US Surgeon General Vivek Murthy believes that cannabis possesses therapeutic utility — an acknowledgment that contradicts the plant’s present placement as a Schedule I controlled substance under federal law.
Speaking to CBS News, Murthy said: “We have some preliminary data showing that for certain medical conditions and symptoms that marijuana can be helpful.” He added, “I think we have to use that data to drive policy making and I’m very interested to see where that data takes us.”
Dr. Murthy was confirmed as US Surgeon General late last year.
His statements appear to be inconsistent with the Schedule I classification of marijuana under federal law — a scheduling that defines the plant and its organic compounds as possessing “no currently accepted medical use …. in the United States” and lacking “accepted safety … under medical supervision.”
Next week in Sacramento, a federal judge will hear final arguments in a motion challenging the constitutionality of cannabis’ Schedule I classification. In October, defense counsel and experts presented evidence over a five day period arguing that the scientific literature is not supportive of the plant’s present categorization.
Briefs in this ongoing federal case are available online here.
[Update: Perhaps predictably, the Surgeon General has dialed back his initial comments to CBS News. Late last night, The Department of Health and Human Services issued a statement attributed to Murthy stating: “Marijuana policy — and all public health policies — should be driven by science. I believe that marijuana should be subjected to the same, rigorous clinical trials and scientific scrutiny that the Food and Drug Administration (FDA) applies to all new medications. The Federal Government has and continues to fund research on possible health benefits of marijuana and its components. While clinical trials for certain components of marijuana appear promising for some medical conditions, neither the FDA nor the Institute of Medicine have found smoked marijuana to meet the standards for safe and effective medicine for any condition to date.”
Interesting that Dr. Murthy cites the IOM which hasn’t formally commented on the issue of medical marijuana since releasing its report some 15 years ago, long before the results of FDA-approved clinical trials like this had been completed. Also notable that he leans on the FDA for guidance when the agency largely does not review the safety and efficacy of botanical products.]
Cannabis use is inversely associated with incidences of bladder cancer in males, according epidemiological findings published in the February issue of the journal Urology.
Investigators at the Kaiser Permanente Los Angeles Medical Center, Department of Neurology assessed the association of cannabis use and tobacco smoking on the risk of bladder cancer in a multiethnic cohort of more than 80,000 men aged 45 to 69 years old over an 11-year period.
Researchers determined that a history of cannabis use was associated with a decreased risk of bladder cancer. By contrast, tobacco use was associated with an increased risk of cancer.
“After adjusting for age, race or ethnicity, and body mass index, using tobacco only was associated with an increased risk of bladder cancer (hazard regression 1.52) whereas cannabis use was only associated with a 45 percent reduction in bladder cancer incidence (HR 0.55),” investigators reported.
Subjects who reported using both tobacco and cannabis possessed a decreased risk of cancer (HR 1.28) compared to those subjects who used tobacco only (HR 1.52).
The study is the first to indicate that cannabis use may be inversely associated with bladder cancer risk.
“In this multiethnic cohort of 82,050 men, we found that cannabis use alone was associated with a decreased risk of bladder cancer. … [M]en who used tobacco alone were 1.5 times more likely to develop bladder cancer when compared with men who did not use tobacco or cannabis. … However, among men who used both substances, this risk of bladder cancer was mitigated. … If this represents a cause and effect relationship, this pathway may provide new opportunities for the prevention and/or treatment of bladder cancer.”
In 2009, Brown University researchers similarly reported that the moderate long-term use of marijuana was associated with a reduced risk of head and neck cancers in a multi-center cohort involving over 1,000 subjects. Investigators further reported that marijuana use “modified the interaction between alcohol and cigarette smoking, resulting in a decreased HNSCC (head and neck squamous cell carcinoma) risk among moderate smokers and light drinkers, and attenuated risk among the heaviest smokers and drinkers.”
Read the abstract of the study, “Association between cannabis use and the risk of bladder cancer: Results from the California Men’s Health Survey,” online here.
An updated policy statement issued today by the American Academy of Pediatrics (AAP) calls for the rescheduling of the cannabis plant under federal law to better facilitate clinical trial research and to promote the plant’s eventual pharmaceutical development.
The new position statement resolves: “The AAP strongly supports research and development of pharmaceutical cannabinoids and supports a review of policies promoting research on the medical use of these compounds. The AAP recommends changing marijuana from a Drug Enforcement Administration schedule I (controlled substance) to a Schedule II drug to facilitate this (clinical) research.”
By definition, schedule I controlled substances are defined as possessing no “accepted medical use.” Clinical protocols involving cannabis are strictly controlled and require authorization from various federal agencies, including DEA, FDA, and the National Institute on Drug Abuse (NIDA) – the latter of which is designated under federal law as the sole provider of cannabis and/or organic cannabinoids for research purposes.
“A Schedule 1 listing means there’s no medical use or helpful indications, but we know that’s not true because there has been limited evidence showing [marijuana] may be helpful for certain conditions in adults,” said Dr. Seth Ammerman, who co-authored the new policy statement.
The newly amended AAP resolution also acknowledges that certain types of cannabinoid-therapy may provide benefits to adolescents, particularly those patient populations with treatment-resistant forms of epilepsy and chronic seizures. It states, “The AAP recognizes that marijuana may currently be an option for cannabinoid administration for children with life-limiting or severely debilitating conditions and for whom current therapies are inadequate.”
Last year the Epilepsy Foundation of America issued a similar resolution, citing preclinical data and observational reports of the potential therapeutic benefit of the cannabinoid cannabidiol (CBD) in pediatric patients and calling for “an end to Drug Enforcement Administration (DEA) restrictions that limit clinical trials and research into medical marijuana for epilepsy.”
Separate language in the AAP’s position statement also addresses the social use of the plant, affirming, “AAP strongly supports the decriminalization of marijuana use for both minors and young adults and encourages pediatricians to advocate for laws that prevent harsh criminal penalties for possession or use of marijuana.” By contrast, the statement acknowledges the group’s continued opposition to the legalization of marijuana, a policy change that it alleges poses “potential harm to children.”
Text of the amended AAP position paper is online here. A summary of resolutions issued by other medical and health organizations in regard to patient access to therapeutic cannabis is available on the NORML website here.
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.