Cannabis vaping and public health--some comments on relevance and implications

Emissions from Heated Terpenoids Present in Vaporizable Cannabis Concentrates

Vaporizable cannabis concentrates (VCCs) consumed as a liquid (vaping) or a waxy solid (dabbing) are becoming increasingly popular. However, their associated emissions and impacts have not been fully described. Mixtures containing different proportions of 12 VCC terpenoids and high MW compounds were heated at 100-500 °C inside a room-sized chamber to simulate emissions. Terpenoids, thermal degradation byproducts, and ultrafine particles (UFPs) were quantified in the chamber air. Air samples contained over 50% of emitted monoterpenes and less than 40% of released sesquiterpenes and terpene alcohols. Eleven degradation byproducts were quantified, including acrolein (1.3-3.9 μg m^-3) and methacrolein (2.0 μg m^-3). A large amount of UFPs were released upon heating and remained airborne for at least 3 h. The mode diameter increased from 80 nm at 100 °C to 140 nm at 500 °C, and particles smaller than 250 nm contributed to 90% of PM_1.0. The presence of 0.5% of lignin, flavonoid, and triterpene additives in the heated mixtures resulted in a threefold increase in the particle formation rate and PM_1.0 concentration, suggesting that these high-molecular-weight compounds enhanced aerosol inception and growth. Predicted UFP emission rates in typical consumption scenarios (6 × 10¹¹-2 × 10¹³ # min^-1) were higher than, or comparable with, other common indoor sources such as smoking and cooking.

Vaporization of Marijuana Among Recreational Users: A Qualitative Study

OBJECTIVE

Vaporization of marijuana products, or "vaping," has become a prevalent mode of administration and is typically perceived to hold unique benefits compared to combustible administration methods. Such positive beliefs regarding marijuana vaporization may contribute to its abuse liability. This qualitative study examined cognitions pertaining to vaping among recreational marijuana users.

METHOD

Focus groups were conducted with frequent marijuana users (N = 31; five groups; six to seven per group; M = 5.0 days/week marijuana use). Three topic areas were queried during discussions with the goal of revealing factors that may contribute to the abuse liability of vaporization. These comprised differences between smoking and vaporizing marijuana products, perceived advantages of vaporization, and perceived disadvantages of vaporization. Focus groups lasted approximately 60 minutes and followed a semistructured agenda; the sessions were audio recorded and transcribed for an applied thematic analysis. An executive summary of each group was made and key themes pertaining to vaporization were summarized.

RESULTS

Several themes emerged, including differences between smoking and vaporizing marijuana, convenience, discretion, and efficiency of vaping, perceived health benefits, the absence of traditional smoking rituals, and the high cost of vaporization devices.

CONCLUSIONS

Several factors appear to promote marijuana vaporization, including device aspects (e.g., discreet, convenient), the subjective high, economical efficiency, and perceived harm-reducing and health-promoting effects. These qualitative data highlight unique cognitions about marijuana vaping that may substantially increase its abuse liability. Quantitative research is needed to examine the extent to which cognitions about marijuana vaporization contribute to actual use patterns and problematic behaviors.

A qualitative analysis of cannabis vaporization among medical users

Cannabis vaporization is a prevailing mode of administration among medical users for symptom relief. Limited research to date has considered factors that contribute to vaporization in medical users, although initial evidence suggests that vaporization may provide unique therapeutic advantages relative to other modes. This study aimed to provide an in-depth qualitative examination of vaping behavior and use preferences among medical cannabis users. Qualitative interviews were conducted with Rhode Island medical cannabis registration card holders (n = 25). Interviews followed a semistructured agenda and were audio-recorded and transcribed for applied thematic analysis. Key vaporization themes were summarized. Several themes emerged related to (a) medication dosing and administration (flexible timing of medication delivery; ease when traveling; type of device/cannabis formulation), (b) physical health advantages of vaping (general health benefits; better for medical condition; promoting tobacco cessation), (c) general advantages of vaping (portability, concealability, efficiency), and (d) disadvantages (weaker medication delivery; device cost; technology-use barriers). Various factors contribute to cannabis vaporization among medical users that are both general and medical-specific. Certain aspects of vaping may also interfere with effective delivery of cannabis, including technology aspects and device cost. These findings highlight the heterogeneity in vaporization behavior. Future work is needed to further identify factors that contribute to the therapeutic efficacy of cannabis and its modalities of use. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Routes of administration for cannabis use - basic prevalence and related health outcomes: A scoping review and synthesis

BACKGROUND

Cannabis use is common, and associated with adverse health outcomes. 'Routes of administration' (ROAs) for cannabis use have increasingly diversified, in part influenced by developments towards legalization. This paper sought to review data on prevalence and health outcomes associated with different ROAs.

METHODS

This scoping review followed a structured approach. Electronic searches for English-language peer-reviewed publications were conducted in primary databases (i.e., MEDLINE, EMBASE, PsycINFO, Google Scholar) based on pertinent keywords. Studies were included if they contained information on prevalence and/or health outcomes related to cannabis use ROAs. Relevant data were screened, extracted and narratively summarized under distinct ROA categories.

RESULTS

Overall, there is a paucity of rigorous and high-quality data on health outcomes from cannabis ROAs, especially in direct and quantifiable comparison. Most data exist on smoking combusted cannabis, which is associated with various adverse respiratory system outcomes (e.g., bronchitis, lung function). Vaporizing natural cannabis and ingesting edibles appear to reduce respiratory system problems, but may come with other risks (e.g., delayed impairment, use 'normalization'). Vaporizing cannabis concentrates can result in distinct acute risks (e.g., excessive impairment, injuries). Other ROAs are uncommon and under-researched.

CONCLUSIONS

ROAs appear to distinctly influence health outcomes from cannabis use, yet systematic data for comparative assessments are largely lacking; these evidence gaps require filling. Especially in emerging legalization regimes, ROAs should be subject to evidence-based regulation towards improved public health outcomes. Concretely, vaporizers and edibles may offer potential for reduced health risks, especially concerning respiratory problems. Adequate cannabis product regulation (e.g., purity, labeling, THC-restrictions) is required to complement ROA-based effects.

U.S. cannabis legalization and use of vaping and edible products among youth

BACKGROUND

Alternative methods for consuming cannabis (e.g., vaping and edibles) have become more popular in the wake of U.S. cannabis legalization. Specific provisions of legal cannabis laws (LCL) (e.g., dispensary regulations) may impact the likelihood that youth will use alternative methods and the age at which they first try the method - potentially magnifying or mitigating the developmental harms of cannabis use.

METHODS

This study examined associations between LCL provisions and how youth consume cannabis. An online cannabis use survey was distributed using Facebook advertising, and data were collected from 2630 cannabis-using youth (ages 14-18). U.S. states were coded for LCL status and various LCL provisions. Regression analyses tested associations among lifetime use and age of onset of cannabis vaping and edibles and LCL provisions.

RESULTS

Longer LCL duration (OR_vaping: 2.82, 95% CI: 2.24, 3.55; OR_edibles: 3.82, 95% CI: 2.96, 4.94), and higher dispensary density (OR_vaping: 2.68, 95% CI: 2.12, 3.38; OR_edibles: 3.31, 95% CI: 2.56, 4.26), were related to higher likelihood of trying vaping and edibles. Permitting home cultivation was related to higher likelihood (OR: 1.93, 95% CI: 1.50, 2.48) and younger age of onset (β: -0.30, 95% CI: -0.45, -0.15) of edibles.

CONCLUSION

Specific provisions of LCL appear to impact the likelihood, and age at which, youth use alternative methods to consume cannabis. These methods may carry differential risks for initiation and escalation of cannabis use. Understanding associations between LCL provisions and methods of administration can inform the design of effective cannabis regulatory strategies.

Prevalence and correlates of "Vaping" as a route of cannabis administration in medical cannabis patients

PURPOSE

To examine the prevalence and correlates of vaporization (i.e., "vaping") as a route of cannabis administration in a sample of medical cannabis patients.

PROCEDURES

Adults ages 21 and older (N=1485M age=45.1) who were seeking medical cannabis certification (either for the first time or as a renewal) at medical cannabis clinics in southern Michigan completed a screening assessment. Participants completed measures of route of cannabis administration, cannabis use, alcohol and other substance use.

FINDINGS

An estimated 39% (n=511) of the sample reported past-month cannabis vaping, but vaping as the sole route of cannabis administration was rare. Specifically, only 30 participants (2.3% of the full sample and 5.9% of those who reported any vaping) indicated vaping as the sole route of cannabis administration. The majority (87.3%) of those who reported vaping also reported smoking (combustion) as a route of cannabis administration. Being younger than age 44, having more than a high school education, engaging in nonmedical stimulant use, being a returning medical cannabis patient, and greater frequency of cannabis use were associated with higher odds of vaping at the bivariate level and with all variables considered simultaneously.

CONCLUSIONS

Vaping appears to be relatively common among medical cannabis patients, but is seldom used as the sole route of cannabis administration.

RESULTS

highlight the importance of monitoring trends in vaping and other substance use behaviors in this population and underscore the need for longitudinal research into the motives, correlates, and consequences of cannabis vaping in medical cannabis patients.

Confirmation of the trials and tribulations of vaping

Responses to our article indicate consensus on the need for expedited scientific and regulatory action related to vaping of cannabis and other substances to curtail untoward public health impact and identify potential benefits. How to speed up science, increase knowledge and enact responsible regulatory policy poses a formidable challenge.