Cannabis smoking and respiratory health: consideration of the literature

Cannabis use is not associated with altered levels of physical activity: evidence from the repeated cross-sectional Belgian Health Interview Survey

BACKGROUND

Several studies have suggested a positive effect of occasional cannabis consumption on the frequency of leisure-time physical activity, possibly due to more motivation before, more enjoyment during, and better recovery after engaging in leisure-time physical exercise. While such an effect would contradict the stereotypical image of lower physical activity levels in cannabis users as compared to non-users, evidence has been mixed at best. The current study investigated this proposed association in a representative sample of the Belgian population.

METHODS

Data from four waves of the Belgian Health Interview Survey (HIS; repeated cross-sectional survey; 2001 - 2018) were used in a regression and propensity matching analysis to examine the association between past-month cannabis use and physical activity levels, while controlling for potentially confounding variables. A total of n = 19,936 individuals (48.9% female) aged 15-64 years were included in the analysis. We modelled physical activity in function of past-month cannabis use while adjusting for potential confounders.

RESULTS

Both the regression analysis and the propensity-matching analysis revealed no evidence in favor of a positive effect of past-month cannabis use on physical activity level (estimated OR = 0.97, 95% CI = [0.74, 1.28] and estimated RR = 0.90, 95% CI = [0.70; 1.16] respectively). Descriptive analyses of baseline characteristics suggested some clear differences between users and non-users that were in line with previous studies.

CONCLUSIONS

There was no evidence suggesting that past-month cannabis users have better or worse physical activity levels compared to non-users in the Belgian population aged 15-64 years.

Examining the Relationship of Cannabis use Patterns, Mental Health, and Sociodemographic Factors: A Focus on Cannabis Vaping, Smoking and Dual-Use

BACKGROUND

Cannabis vaping, and co-use with cannabis smoking, can exacerbate the risks of developing respiratory diseases and cannabis dependence. This study aims to examine the mental health profiles and sociodemographic correlates of adults who vape cannabis and engage in dual cannabis use (vaping/ smoking), compared to those who smoke cannabis.

METHODS

The most recent, cross-sectional wave of the Population Assessment of Tobacco and Health Study (Wave 6) was used in this study. Data were restricted to adults (18 + years) who currently use cannabis (n = 7,178). Participants were classified as 'cannabis smoking only,' 'cannabis vaping only,' 'dual-use,' or 'other cannabis use methods only.' Multinomial logistic regression was used to examine the sociodemographic, internalizing and externalizing symptom factors of cannabis vaping and dual-use compared to cannabis smoking.

RESULTS

Over 56 % of participants currently smoked cannabis only, 9.1 % vaped cannabis only, while 20.0 % were engaging in dual-use. Adults experiencing severe externalizing symptoms (vs. mild symptoms) had higher odds of engaging in dual-use than smoking cannabis only (OR = 1.89, 99.5 %CI: 1.48, 2.40). Those with White racial background (vs. African-American background) (OR = 3.90, 99.5 %CI: 2.31, 6.58) and earning a higher income (vs. lower income) (OR = 2.56, 99.5 %CI: 1.79, 3.66) had higher odds of currently vaping cannabis only, compared to smoking cannabis only.

CONCLUSIONS

Our study has identified that mental health plays a significant role in cannabis use patterns, particularly with externalizing symptoms which are related to aggression and diagnoses of attention deficit disorders. This highlights the need for healthcare and mental health providers to address mental health symptoms when managing adult cannabis use.

Exploring the Antioxidant and Anti-Inflammatory Effects of Rhoifolin Isolated from Teucrium Polium on Rats' Lungs Exposed to Tobacco Smoke

Cigarette smoking exacerbates respiratory diseases, while plant-derived polyphenols offer antioxidant and anti-inflammatory benefits. This study exploresd the effects of Rhoifolin (ROF), a polyphenol from Jordanian Teucrium polium, on lung health in rats exposed to tobacco smoke. Male rats were divided into two groups: one exposed to cigarette smoke (CS), and the other to ROF treatment alongside smoke exposure (CS/ROF). ROF was administered orally for 21 days before smoke exposure. Results showed smoke-induced lung inflammation and oxidative stress, mitigated by ROF treatment. Histological examination revealed smoke-related morphological changes in lung tissue. ROF treatment reduced oxidative stress and inflammation, as evidenced by decreased proinflammatory cytokines. In silico docking demonstrated ROF's potential as an inhibitor of proinflammatory cytokines. This study demonstrates the therapeutic potential of ROF and similar polyphenols in mitigating the harmful effects of cigarette smoke on lung health.

An examination of cannabis use motives among couples with intimate partner violence and alcohol use disorder

BACKGROUND AND OBJECTIVES

Cannabis use is highly prevalent among individuals with a history of intimate partner violence (IPV) and among people who drink alcohol. Motives for cannabis use are important correlates of consumption and problem severity. However, no research has examined cannabis use motives among couples with IPV. The goals of the study were to examine (1) the associations between a person and their partner's cannabis use motives; and (2) examine the extent to which each partners' cannabis use motives are related to their own and their partner's cannabis consumption.

METHODS

Participants were 100 couples (n = 92 different-sex couples, n = 8 same-sex couples) who reported physical IPV in their current relationship.

RESULTS

Certain cannabis motives (coping and conformity) and behaviors (cannabis use frequency, quantity and drug-related problems) were positively associated between intimate partners. One's own higher coping motives were associated with greater frequency of cannabis consumption; higher conformity motives were associated with less quantity of consumption; higher social motives were associated with greater quantity of cannabis consumption; and one's partner's social motives were associated with less quantity of cannabis consumption. DISCUSSION AND CONCLUSIONS: Findings suggest that couples report similar motives for cannabis use, and that one's own and their partner's motives may differentially influence frequency and quantity of use.

SCIENTIFIC SIGNIFICANCE

This study provides novel information on congruency between cannabis use motives and behaviors between intimate partners, as well as how both an individual and their partner's motives for use can influence an individual's cannabis use behaviors.

Assessing dental student knowledge on cannabis and demonstrating the need for cannabis education

PURPOSE

The American Dental Association advocates for dentists' education on therapeutic and legal issues related to medical cannabis. It is important to understand current knowledge of cannabis and cannabinoids and to have a practical knowledge assessment instrument. This exploratory study is the first of its kind to assess dental students' knowledge of cannabis and aims to determine if there is a need for more instruction regarding cannabis in a dental school's curriculum.

METHODS

Predoctoral dental students at the University at Buffalo School of Dental Medicine were recruited to participate. A validated, anonymous 22-item online survey was adapted and administered to students in all 4 years of the dental program. There was a total of 56 knowledge points.

RESULTS

The average knowledge score was 21.6 points (SD = 5.2, range: 7-34), corresponding to 38.5% (SD = 9.2) of the answers correct. There were no overall differences in knowledge by gender, years in dental school, or by any reported source of formal education on cannabis. Those who reported doing their own research had higher knowledge scores. Most participants knew that there is an endogenous cannabinoid system (72.3%) and that Tetrahydrocannabinol (THC) is responsible for the "high" experienced with cannabis (76.6%). Most participants reported that they did not know the effective doses of THC (58.2%) and Cannabidiol (CBD) (66.7%); few provided an answer for THC (34%) or CBD (17%) in the acceptable range of 2-10 mg.

CONCLUSION

Dental students did not have adequate knowledge on cannabis and cannabinoids. Given the rapid expansion of cannabis legalization, additional efforts are needed to integrate cannabis topics into coursework and learning experiences.

Exercise capacity, lung and respiratory muscle function in substance use disorders

BACKGROUND

Substance use disorder (SUD) causes conditions such as cognitive and behavioral disorders, anxiety, depression, and social isolation it also causes acute airway inflammation by affecting airway bronchial dynamics. The current study aimed to investigate the lung function, respiratory muscle strength, and exercise capacity in patients with SUD.

METHODS

One hundred-eighty three patients with SUD, a total of 119 healthy controls, 54 of whom were cigarette smokers and 65 of whom were non-smokers were included in the study. Spirometric tests, respiratory muscle strength (MIP and MEP), and the 6-Minute Walk Test (6-MWT) were assessed. The III National Health and Nutrition Examination Survey were used to evaluate respiratory symptoms in patients with SUD and cigarette smokers.

RESULTS

86.3% of the SUD patients included in the study were using heroin, 9.2% were cannabis, and 5.5% were spice. The most common symptom in both SUD patients and cigarette smokers was shortness of breath, wheezing, and sputum production. After post-hoc tests, the FVC (p = 0.002), FVC (%predicted) (p < 0.0001), FEV1 (p = 0.002), FEV1 (%predicted) (p < 0.0001), FEV1/FVC (%) (p < 0.0001), PEF (p < 0.0001) and FEF%25-75 (p < 0.0001) lung function parameters were significantly lower in SUD patients than non-smokers. In addition, it was found that MIP (p < 0.0001), MIP (%predicted) (p < 0.0001), MEP (p < 0.0001), and MEP (%predicted) (p < 0.0001) values of SUD patients were significantly lower than non-smokers.

CONCLUSION

The study findings indicate that substance use has an effect on lung functions and the most commonly reported symptoms are shortness of breath, wheezing, and sputum production. In addition, respiratory muscle strength and exercise capacity were decreased in SUD patients compared to non-smokers.

Effects of cannabis smoking on the respiratory system: A state-of-the-art review

The diminished perception of the health risks associated with the consumption of cannabis (marijuana) lead to a progressive increase in its inhalational use in many countries. Cannabis can be smoked through the use of joints, spliffs and blunts, and it can be vaporised with the use of hookah or e-cigarettes. Delta-9 tetrahydrocannabinol (THC) is the main psychoactive component of cannabis smoke but contains numerous other substances. While the recreational use of cannabis smoking has been legalised in several countries, its health consequences have been underestimated and undervalued. The purpose of this review is to critically review the impact of cannabis smoke on the respiratory system. Cannabis smoke irritates the bronchial tree and is strongly associated with symptoms of chronic bronchitis, with histological signs of airway inflammation and remodelling. Altered fungicidal and antibacterial activity of alveolar macrophages, with greater susceptibility to respiratory infections, is also reported. The association with invasive pulmonary aspergillosis in immunocompromised subjects is particularly concerning. Although cannabis has been shown to produce a rapid bronchodilator effect, its chronic use is associated with poor control of asthma by numerous studies. Cannabis smoking also represents a risk factor for the development of bullous lung disease, spontaneous pneumothorax and hypersensitivity pneumonitis. On the other hand, no association with the development of chronic obstructive pulmonary disease was found. Finally, a growing number of studies report an independent association of cannabis smoking with the development of lung cancer. In conclusion, unequivocal evidence established that cannabis smoking is harmful to the respiratory system. Cannabis smoking has a wide range of negative effects on respiratory symptoms in both healthy subjects and patients with chronic lung disease. Given that the most common and cheapest way of assumption of cannabis is by smoking, healthcare providers should be prepared to provide counselling on cannabis smoking cessation and inform the public and decision-makers.

Changes in lung function in adolescents with substance use disorders: an exploratory study

OBJECTIVE

To compare lung function between adolescents with and without substance use disorder (SUD).

METHODS

This was an observational, cross-sectional exploratory study. The sample consisted of 16 adolescents with SUD and 24 age-matched healthy controls. The adolescents in the clinical group were recruited from a psychiatric inpatient unit for detoxification and rehabilitation; their primary diagnosis was SUD related to marijuana, cocaine, or polysubstance use. Questionnaires and pulmonary function tests were applied for clinical evaluation.

RESULTS

We found that FVC, FEV1, and their percentages of the predicted values were significantly lower in the adolescents with SUD than in those without. Those differences remained significant after adjustment for BMI and the effects of high levels of physical activity. The largest effect size (Cohen's d = 1.82) was found for FVC as a percentage of the predicted value (FVC%), which was, on average, 17.95% lower in the SUD group. In addition, the years of regular use of smoked substances (tobacco, marijuana, and crack cocaine) correlated negatively with the FVC%.

CONCLUSIONS

This exploratory study is innovative in that it demonstrates the early consequences of smoked substance use for the lung health of adolescents with SUD.

Cannabis use for Sleep Disturbance Among Older Patients in a Geriatrics Clinic

Cannabis use is growing among older adults to manage medical concerns including poor sleep. In this study, we characterized how patients seen at a geriatrics clinic use cannabis to address sleep disturbance. Specifically, we conducted an anonymous survey of 568 adults, including 83 who reported cannabis use within the past 3 years, to inquire about such use. We compared cannabis use characteristics between those using it for sleep disturbance versus all other conditions. We considered a p-value <.10 to be statistically significant. Among the cannabis users in our sample, 29% reported using cannabis for sleep disturbance (N = 24). They were more likely than other users to be female (p = .07), consume cannabis more frequently (p = .01), use products containing tetrahydrocannabinol (THC) (vs. cannabidiol [CBD]-only; p < .01), and use cannabis to target more symptoms (p < .01). As cannabis use continues to grow in older populations, it is essential to delineate better how cannabis may be used safely and effectively to improve older adults' sleep health.

[Diffuse alveolar hemorrhage in cannabis smokers. A systematic literature review]

Cannabis is the most widely used illicit psychoactive substance in France. It can be responsible for numerous pulmonary complications, including diffuse alveolar hemorrhage (DAH). The objective of this systematic review of the literature was to present data concerning the relationship between cannabis smoking and DAH, which has rarely been reported in the literature. The review was based on a Medline search covering the 1980-2022 period and utilizing data drawn from 10 articles. DAH diagnosis is based on an association of hemoptysis, anemia and diffuse alveolar opacities on chest radiography with siderophages in the Bronchoalveolar Lavage Fluid (BAL). The 11 patients identified in this review were daily or regular cannabis smokers; in 4 cases they presented recent or recurrent hemoptysis with anemia; imaging revealed diffuse alveolar opacities in 10 of them, while BAL endoscopy highlighted a diffuse hemorrhage in the bronchial tree, and siderophages were observed in 6 cases. While evolution was favorable when cannabis consumption was discontinued, resumption occasioned DAH recurrence, and one patient died. Advice to quit should systematically be accompanied by addictological follow-up.

Income inequality and daily use of cannabis, cigarettes, and e-cigarettes among Canadian secondary school students: Results from COMPASS 2018-19

INTRODUCTION

Cannabis, cigarette, and e-cigarette use among Canadian adolescents is a major public health concern. Income inequality has been associated with adverse mental health among youth and may contribute to the risk of frequent cannabis, cigarette, and e-cigarette use. We tested the association between income inequality and the risk of daily cannabis, cigarette, and e-cigarette use among Canadian secondary school students.

METHODS

We used individual-level survey data from Year 6 (2018/19) of Cannabis, Obesity, Mental health, Physical activity, Alcohol use, Smoking, and Sedentary Behavior (COMPASS) and area-level data from the 2016 Canadian Census. Three-level logistic models were used to assess the relationship between income inequality and adolescent daily and current cannabis use, cigarette smoking, and e-cigarette use.

RESULTS

The analytic sample included 74,501 students aged 12-19. Students were most likely to report being male (50.4%), white (69.1%), and having weekly spending money over $100 (23.5%). We found that a standard deviation unit increase in Gini coefficient was significantly associated with increased likelihood of daily cannabis use (OR=1.25, 95% CI = 1.01-1.54) when adjusting for relevant covariates. We found no significant relationship between income inequality and daily smoking. While Gini was not significantly associated with daily e-cigarette use, we observed a significant interaction between Gini and gender (OR=0.87, 95% CI= 0.80-0.94), indicating that increased income inequality was associated with higher risk of reporting daily e-cigarette use among females only.

DISCUSSION

An association between income inequality and the likelihood of reporting daily cannabis use across all students and daily e-cigarette use in females were observed. Schools in higher income inequality areas may benefit from targeted prevention and harm reduction programs. Results emphasize the need for upstream discussion on policies that can mitigate the potential effects income inequality.

The endocannabinoid system and breathing

Recent changes in cannabis accessibility have provided adjunct therapies for patients across numerous disease states and highlights the urgency in understanding how cannabinoids and the endocannabinoid (EC) system interact with other physiological structures. The EC system plays a critical and modulatory role in respiratory homeostasis and pulmonary functionality. Respiratory control begins in the brainstem without peripheral input, and coordinates the preBötzinger complex, a component of the ventral respiratory group that interacts with the dorsal respiratory group to synchronize burstlet activity and drive inspiration. An additional rhythm generator: the retrotrapezoid nucleus/parafacial respiratory group drives active expiration during conditions of exercise or high CO₂. Combined with the feedback information from the periphery: through chemo- and baroreceptors including the carotid bodies, the cranial nerves, stretch of the diaphragm and intercostal muscles, lung tissue, and immune cells, and the cranial nerves, our respiratory system can fine tune motor outputs that ensure we have the oxygen necessary to survive and can expel the CO₂ waste we produce, and every aspect of this process can be influenced by the EC system. The expansion in cannabis access and potential therapeutic benefits, it is essential that investigations continue to uncover the underpinnings and mechanistic workings of the EC system. It is imperative to understand the impact cannabis, and exogenous cannabinoids have on these physiological systems, and how some of these compounds can mitigate respiratory depression when combined with opioids or other medicinal therapies. This review highlights the respiratory system from the perspective of central versus peripheral respiratory functionality and how these behaviors can be influenced by the EC system. This review will summarize the literature available on organic and synthetic cannabinoids in breathing and how that has shaped our understanding of the role of the EC system in respiratory homeostasis. Finally, we look at some potential future therapeutic applications the EC system has to offer for the treatment of respiratory diseases and a possible role in expanding the safety profile of opioid therapies while preventing future opioid overdose fatalities that result from respiratory arrest or persistent apnea.

Cannabis smoking and age-related macular degeneration in the UK Biobank cohort

BACKGROUND

A major cause of blindness in older persons is age-related macular degeneration (AMD). Cigarette smoking is one of the major risk factors for AMD. In the present study, we analyzed UK Biobank data to determine whether smoking cannabis, like cigarettes, might be related to AMD.

METHODS

Our UK Biobank application was approved as UKB project 57245 (S.L., P.H.R.). Our analysis included all subjects with AMD and cannabis smoking information. The diagnosis of AMD was ascertained based on the 10th Revision of the International Classification of Diseases (ICD10), H35.3. Age at time of diagnosis of AMD was obtained from data field 5923. Cannabis information was recorded in UKB category 143, data field 20453, ever taken cannabis. A touch screen posed the question, "Have you taken CANNABIS (cannabis, grass, hash, ganja, blow, draw, skunk, weed, spliff, dope), even if it was a long time ago?" Possible answers were no, yes, 1-2 times, yes 3-10 times, yes, 11-100 times, yes, more than 100 times.

RESULTS

Subjects who had used marijuana more than 100 times had a significantly reduced risk of AMD, compared to subjects who had never used marijuana, and use of marijuana every day was associated with less AMD than use of marijuana less than once a month. But subjects who used cannabis 100 times or more were significantly younger (8years) when they developed AMD than subjects who never used cannabis.

CONCLUSION

Drusen, deposits of lipids, proteins, and cellular debris, accumulate in Bruch's membrane, limiting transport between the retinal pigment epithelium and the vasculature, triggering an inflammatory reaction. Marijuana can retard the inflammatory process because it is a powerful anti-inflammatory agent. Therefore, marijuana could reduce the risk of AMD. At the same time, blood vessels in the choriocapillaris below Bruch's membrane become more sparse with age. This phenomenon is believed to be a starting point for AMD. Marijuana can accelerate the loss of blood vessels due to its anti-angiogenic properties. Therefore, marijuana use might cause AMD to develop sooner in younger people.

A description of self-medication with cannabis among adults with legal access to cannabis in Quebec, Canada

Objective

Cannabis is increasingly used for medical purposes, particularly in countries like Canada where cannabis was recently legalized for recreational use. We aimed to assess self-medication with cannabis post-cannabis legalization among adults in the Canadian province of Quebec.

Methods

This is a cross-sectional online survey of a self-selected convenience sample conducted in Quebec, Canada, from November 2020 to January 2021. Individuals aged ≥ 21 years who endorsed using cannabis bought in legal recreational cannabis stores to self-medicate a health condition were included. Data were analyzed using descriptive statistics and stratified according to sex, age, and the type of cannabis use (exclusively medical versus medical and recreational use).

Results

Four hundred eighty-nine participants were included. The median age was 34 years, and 48% were women. About 25% reported exclusive medical use of cannabis. Treated conditions included anxiety (70%), insomnia (56%), pain (53%), depression (37%), and many others. Reasons for not consulting in cannabis clinics included lack of information (52%), the complexity of the process (39%), accessibility of cannabis clinics (23%), and others.

Tetrahydrocannabinol (THC) dosage > 20% was reported by 32%. Smoking was the main route of use (81%). Possession of prescribed drugs was reported by 56%. Professionals consulted for information on cannabis included recreational cannabis store agents (36%), physicians (29%), and others.

Overall, significant differences were observed for many of the comparisons according to sex, age, and the type of cannabis use.

Conclusions

Many conditions are self-medicated with cannabis. The use of high doses of cannabis, smoking as a preferred method of use, and concurrent use of other medications may pose some risks to individuals. Addressing the reported barriers to medical access to cannabis is urgently needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42238-022-00135-y.

Cannabis for Medical Use: Versatile Plant Rather Than a Single Drug

Medical Cannabis and its major cannabinoids (−)-trans-Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD) are gaining momentum for various medical purposes as their therapeutic qualities are becoming better established. However, studies regarding their efficacy are oftentimes inconclusive. This is chiefly because Cannabis is a versatile plant rather than a single drug and its effects do not depend only on the amount of THC and CBD. Hundreds of Cannabis cultivars and hybrids exist worldwide, each with a unique and distinct chemical profile. Most studies focus on THC and CBD, but these are just two of over 140 phytocannabinoids found in the plant in addition to a milieu of terpenoids, flavonoids and other compounds with potential therapeutic activities. Different plants contain a very different array of these metabolites in varying relative ratios, and it is the interplay between these molecules from the plant and the endocannabinoid system in the body that determines the ultimate therapeutic response and associated adverse effects. Here, we discuss how phytocannabinoid profiles differ between plants depending on the chemovar types, review the major factors that affect secondary metabolite accumulation in the plant including the genotype, growth conditions, processing, storage and the delivery route; and highlight how these factors make Cannabis treatment highly complex.

Cannabis smoking and glaucoma in the UK Biobank cohort

BACKGROUND

Cigarette smoking is a well-known risk factor for primary open-angle glaucoma (POAG). Tobacco smoke contains a variety of chemicals, including nicotine, free radicals, and carbon monoxide, all of which can play a role in the development of POAG. Cannabis smoke, like tobacco smoke, contains a comparable variety of carcinogenic and toxic compounds. In the present study, we analyzed UK Biobank data to determine whether smoking cannabis, like cigarettes, might be related to POAG.

METHODS

Our analysis included all subjects with glaucoma and cannabis smoking information. Data processing was performed on Minerva, a Linux mainframe with Centos 7.6, at the Icahn School of Medicine at Mount Sinai. We used the UK Biobank Data Parser (ukbb parser), a python-based package that allows easy interfacing with the large UK Biobank dataset. Statistical analysis was performed with SPSS 25 and R.

RESULTS

Subjects who used cannabis 100 times or more were significantly younger (10years) when they developed glaucoma than subjects who never used cannabis. The effects of age (P<0.001) and cigarettes (P=0.014) on POAG incidence were significant, but the effect of cannabis use was not (P=0.662). The effect of cannabis use on age at glaucoma diagnosis was significant and unrelated to the effects on intraocular pressure or cigarette pack-years smoked. Analysis of intraocular pressure showed that mean pressures of subjects who used cannabis 11-100 times were significantly lower than those who took no cannabis.

CONCLUSION

Inhaling cannabis smoke is injurious to the eye, but in the case of glaucoma the manifestations are different from those of inhaled tobacco smoke. Cannabis reduces intraocular pressure but accelerates glaucoma development. Cannabis does not increase risk of glaucoma. Cigarette smoking increases risk of glaucoma and significantly accelerates glaucoma development. Apparently, early use of cannabis leads to the earlier development of glaucoma.

Marijuana smoking and cataract

BACKGROUND

Cigarette smoking is a well-known risk factor for cataract and other ailments, including heart disease, lung cancer, and chronic obstructive pulmonary disease. Cannabis smoke, like tobacco smoke, contains a comparable variety of carcinogenic and toxic compounds.

PURPOSE

In the present study, we analyzed UK Biobank data to determine whether smoking cannabis, like cigarettes, might be related to cataract.

METHODS

Our analysis included all UK Biobank subjects with cataracts and information on cannabis and cigarette smoking habits. The diagnosis of cataract was ascertained using the 10th Revision of the International Classification of Diseases (ICD10), H25. The age at diagnosis of cataract was obtained from UK Biobank data field 4700. Cannabis information was recorded in UK Biobank category 143, data field 20453, ever taken cannabis.

RESULTS

Subjects who used cannabis 11-100 times or more were significantly younger (4-5 years) when they developed cataract than subjects who never used cannabis. To determine the relationship of current cigarette smoking to cannabis use and age at cataract, the univariate general linear model of SPSS was used, dependent variable age at cataract, fixed factor cannabis use, random factor pack years of cigarettes smoked. Cannabis use was significantly related to age at cataract diagnosis (P<0.001) and independent of the effect of pack-years of cigarettes smoked (P=0.008). Linear regression revealed an insignificant relationship between pack-years of cigarette smoking and age at cataract diagnosis (P=0.073). To further evaluate the relationship of cannabis to cataract, propensity score matching was performed. We identified 28,432 subjects with cataract. Current cigarette smoking and age were covariates; cannabis use (yes/no) was the indicator variable. Current cigarette smoking was significantly associated with a 1.2 odds ratio for cataract. Cannabis use was not significantly associated with the odds ratio for cataract.

CONCLUSION

Like tobacco smoke, cannabis smoke contains thousands of organic and inorganic chemical compounds. Cannabis tar is chemically similar to tar found in tobacco smoke, and over fifty known carcinogens have been identified in cannabis smoke, including nitrosamines, reactive aldehydes, and polycyclic hydrocarbons. Thus, the association of cannabis with cataract that we report here is not entirely surprising. Further studies are warranted.

Concurrent use of e-cigarettes and cannabis and associated COVID-19 symptoms, testing, and diagnosis among student e-cigarette users at four U.S. Universities

Introduction

This investigation assessed whether current (past 30-day) electronic cigarette (e-cigarette) and cannabis use was associated with coronavirus disease 2019 (COVID-19) symptomatology, testing, and diagnosis among college student e-cigarette users.

Methods

Participants were 18–26-year-old college student e-cigarette users attending four geographically diverse, large U.S. public universities during October-December 2020 (N = 800). Multivariable logistic regression models explored associations between exclusive e-cigarette use and concurrent e-cigarette and cannabis use and COVID-19 symptoms, testing, and diagnosis. Models controlled for demographics, university site, and current use of combustible cigarettes, cigars, and smokeless tobacco.

Results

Over half of student e-cigarette users (52.0%) concurrently used cannabis. Compared to exclusive e-cigarette users, concurrent e-cigarette and cannabis users were 3.53 times more likely (95%CI = 1.96–6.36) to report COVID-19 symptoms, after adjusting for the covariates. Compared to infrequent exclusive e-cigarette users, infrequent concurrent users (AOR = 4.72, 95%CI = 1.31–17.00), intermediate concurrent users (AOR = 5.10, 95%CI = 1.37–18.97), and frequent concurrent users (AOR = 7.44, 95%CI = 2.06–26.84) were at increased odds of reporting COVID-19 symptoms. Compared to exclusive e-cigarette users, concurrent e-cigarette and cannabis users were 1.85 times more likely (95%CI = 1.15–2.98) to report a COVID-19 diagnosis. Intermediate concurrent users (AOR = 2.88, 95%CI = 1.13–7.35) and frequent concurrent users (AOR = 3.22, 95%CI = 1.32–7.87) were at increased odds of reporting a COVID-19 diagnosis, compared to infrequent exclusive e-cigarette users.

Conclusions

Concurrent use of e-cigarettes and cannabis may be an underlying risk factor of COVID-19 symptomatology and diagnosis, with more pronounced odds found among intermediate and frequent users. Results highlight the need to educate students about the impacts of e-cigarette and cannabis use on respiratory, immune, and overall health.

Clinical Approaches to Cannabis: A Narrative Review

Cannabis use in the United States is growing at an unprecedented pace. Most states in the United States have legalized medical cannabis use, and many have legalized nonmedical cannabis use. In this setting, health care professionals will increasingly see more patients who have questions about cannabis use, its utility for medical conditions, and the risks of its use. This narrative review provides an overview of the background, pharmacology, therapeutic use, and potential complications of cannabis.

More harm than good? Cannabis, harm and the misuse of drugs act

Purpose

This paper aims to consider the nature of cannabis-related harms under the UK’s Misuse of Drugs Act (MDA). Written for the specific context of this four-paper special section on 50 years of the MDA, it argues that the MDA may cause more harm than it prevents.

Design/methodology/approach

An opinion piece offering a structured overview of cannabis-related harms under prohibition. It summarises existing evidence of the ways in which prohibition may exacerbate existing – and create new – harms related to the production, distribution, use and control of cannabis.

Findings

The paper argues that prohibition of cannabis under the MDA may cause more harm than it prevents.

Originality/value

It has long been argued that the MDA does not accurately or fairly reflect the harms of the substances it prohibits, and much existing research points to different ways in which drug prohibition can itself be harmful. The originality of this paper lies in bringing together these arguments and developing a framework for analysing the contribution of prohibition to drug-related harm.

The potential of cannabinoids and inhibitors of endocannabinoid degradation in respiratory diseases

The global incidence of respiratory diseases and complications is increasing. Therefore, new methods of treatment, as well as prevention, need to be investigated. A group of compounds that should be considered for use in respiratory diseases is cannabinoids. There are three groups of cannabinoids - plant-derived phytocannabinoids, synthetic cannabinoids, and endogenous endocannabinoids including the enzymes responsible for their synthesis and degradation. All cannabinoids exert their biological effects through either type 1 cannabinoid receptors (CB₁) and/or type 2 cannabinoid receptors (CB₂). In numerous studies (in vitro and in vivo), cannabinoids and inhibitors of endocannabinoid degradation have shown beneficial anti-inflammatory, antioxidant, anti-cancer, and anti-fibrotic properties. Although in the respiratory system, most of the studies have focused on the positive properties of cannabinoids and inhibitors of endocannabinoid degradation. There are few research reports discussing the negative impact of these compounds. This review summarizes the properties and mechanisms of action of cannabinoids and inhibitors of endocannabinoid degradation in various models of respiratory diseases. A short description of the effects selected cannabinoids have on the human respiratory system and their possible use in the fight against COVID-19 is also presented. Additionally, a brief summary is provided of cannabinoid receptors properties and their expression in the respiratory system and cells of the immune system.

Effect of Cannabis Smoke Condensate on C. albicans Growth and Biofilm Formation

The most common use of cannabis is smoking. The oral ecosystem, among other constituents, can be deregulated by the presence of cannabis smoke in the oral cavity. We evaluated the effect of cannabis smoke condensate (CSC) on the behavior of Candida albicans, a common yeast found in the oral cavity. The yeast was first cultured with different concentrations of CSC, and its growth was evaluated. The transition from the blastospore to the hyphal form and the hyphae size were assessed after 3 and 6 h, along with biofilm formation after 72 h of contact with CSC. The response of C. albicans to oxidative (H₂O₂) stress was also examined. Our results show that CSC contained high amounts of THC (about 1055 ppm), CBN (63 ppm), and CBG (about 47 ppm). The presence of various concentrations of CSC in the culture medium increased C. albicans growth. CSC also contributed to increases in both the hyphal length and biofilm mass. Following oxidative stress (H₂O₂ at either 100 or 500 μM), CSC prevented the damaging effect of H₂O₂ on both C. albicans shape and growth. These findings support clinical observations demonstrating that cannabis may promote C. albicans growth and oral candidiasis.

Cannabis Abuse and Perioperative Complications Following Inpatient Spine Surgery in the United States

MINI

Due to its complicated legal status, the effects of cannabis on elective spine surgery patients have not been well studied. In this nationwide analysis, we find that cannabis abuse is associated with higher perioperative thromboembolism and neurologic complications, respiratory complications, sepsis, length of stay, hospital charges, and rates of unfavorable discharge disposition.

Decreasing perceived risk associated with regular cannabis use among older adults in the United States from 2015 to 2019

BACKGROUND/OBJECTIVES

Cannabis use among older adults is increasing sharply in the United States. While the risks and benefits of cannabis use remain unclear, it is important to monitor risk factors for use, including low perception of harm. The objective of this study was to estimate recent national trends in perceived risk associated with cannabis use among older adults.

DESIGN

Trend analysis.

SETTING/PARTICIPANTS

A total of 18,794 adults aged 65 and older participating in the 2015-2019 National Survey on Drug Use and Health, a cross-sectional nationally representative survey of non-institutionalized individuals in the United States.

MEASUREMENTS

We estimated the prevalence of older adults who believe that people who smoke cannabis once or twice a week are at great risk of harming themselves physically and in other ways. This was examined across cohort years and stratified by demographic characteristics, diagnosis of chronic disease, past-month tobacco and binge alcohol use, and all-cause emergency department use.

RESULTS

Between 2015 and 2019, perceived risk associated with regular use decreased from 52.6% to 42.7%, an 18.8% relative decrease (p < 0.001). Decreases in perceived risk were detected in particular among those never married (a 32.6% relative decrease), those who binge drink (a 31.3% relative decrease), use tobacco (a 26.8% relative decrease), have kidney disease (a 32.1% relative decrease), asthma (a 31.7% relative decrease), heart disease (a 16.5% relative decrease), chronic obstructive pulmonary disease (a 21.5% relative decrease), two or more chronic conditions (a 20.2% relative decrease), and among those reporting past-year emergency department use (a 21.0% relative decrease) (ps < 0.05).

CONCLUSIONS

The perceived risk of regular cannabis use is decreasing among older adults. We detected sharp decreases in risk perception among those with chronic disease and high-risk behaviors, including tobacco and binge alcohol use. As the number of older adults who use cannabis increases, efforts are needed to raise awareness of the possible adverse effects with special emphasis on vulnerable groups.

High school sport participation and substance use: A cross-sectional analysis of students from the COMPASS study

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Over half the sample did not participate in any school sports.

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32% of youth reported use of one or more substances.

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Intramurals were negatively associated with cannabis and cigarette use.

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Varsity sports were associated with lower odds of cigarette use.

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Varsity sports were associated with increased odds of binge drinking and e-cigarette use.

Introduction

The objective of this study was to examine the association between participation in school sports and substance use behaviors in both male and female high school students.

Methods

The current study used cross-sectional data from 60,601 students from Year 6 (2017–2018) of the COMPASS study. Students reported their school physical activity participation (none, intramurals only, varsity only, both) and past 30-day substance use (binge drinking, cannabis use, cigarette use, e-cigarette use). Hierarchical logistic regression models predicted the odds of substance use, by sex.

Results

55% of students did not participate in any school sports and 32% reported substance use. Intramurals were negatively associated with cannabis use and cigarette use among all students and e-cigarette use among females. Varsity sports were associated with lower odds of cigarette use among all students and cannabis use among males. In contrast, participating in varsity sports was associated with increased odds of binge drinking and e-cigarette use among all students. Participating in both intramurals and varsity sports was associated with increased odds of binge drinking and e-cigarette use but with decreased odds of cannabis use and cigarette use.

Conclusions

Intramurals were found to be protective against cannabis use and cigarette use among all students and e-cigarette use among females. Although varsity sports were protective against cannabis and cigarette use, they were found to be a risk factor for binge drinking and e-cigarette use. Substance use prevention efforts should be a focus among school varsity sports teams, especially for binge drinking and e-cigarette use.

COVID-19 and persons with substance use disorders: Inequities and mitigation strategies

The COVID-19 pandemic disproportionately disrupts the daily lives of marginalized populations. Persons with substance use disorders are a particularly vulnerable population because of their unique social and health care needs. They face significant harm from both the pandemic itself and its social and economic consequences, including marginalization in health care and social systems. Hence, we discuss: (1) why persons with substance use disorders are at increased risk for infection with COVID-19 and a severe illness course; (2) anticipated adverse consequences of COVID-19 in persons with substance use disorders; (3) challenges to health care delivery and substance use treatment programs during and after the COVID-19 pandemic; and (4) the potential impact on clinical research in substance use disorders. We offer recommendations for clinical, public health, and social policies to mitigate these challenges and to prevent negative outcomes.

Co-occurring Use of Cannabis and Tobacco and the Presence of Acute Respiratory Symptoms among Young Adult Light and Intermittent Smokers

BACKGROUND

Cannabis use and intermittent smoking are becoming increasingly prevalent among young adults. Thus, identifying health consequences of co-occurring use of these substances represents an emerging research priority. Purpose/Objectives: This study evaluated the relationship between tobacco/cannabis co-use and acute symptoms of respiratory illness among young adult intermittent smokers. We hypothesized that tobacco/cannabis co-use would be more strongly associated with respiratory symptoms relative to use of neither or one product. Methods: A secondary analysis of a three-year observational study was conducted. Non-daily smokers (n = 563) aged 18-24 were recruited via social media and completed electronic surveys at baseline and annually for two years, producing three total assessments. Past-two-week use of tobacco and cannabis was measured at each assessment, as was severity of six acute respiratory symptoms. The respiratory measure was dichotomized to indicate the presence or absence of symptoms. Results: Tobacco/cannabis co-use decreased from 54.8% at baseline to 43.4% at year two (p < .001). Mean respiratory symptoms also declined significantly over time (ps < .05). At each timepoint, co-use was more strongly associated with presence of respiratory symptoms than the use of neither product (aORs = 2.73-4.39, ps ≤ .013). Co-users were also 38%-183% more likely to endorse the presence of respiratory symptoms than single product users at each timepoint (aORs = 1.38-2.83, ps = .023-.212). Conclusions/Importance: Although co-occurring use of tobacco and cannabis by young adults may represent experimental use of multiple substances, it may also promote or exacerbate acute symptoms of respiratory illness. Further exploration with more granular patterns of co-use and across different routes of administration is warranted.

Medical Reasons for Marijuana Use, Forms of Use, and Patient Perception of Physician Attitudes Among the US Population

BACKGROUND

The use of marijuana for medical purposes is increasing in parallel with expanding legalization and decreased public perception of harm. Despite this increase in use, it is unclear which medical conditions patients are attempting to treat with marijuana and whether they are communicating with medical providers about their use.

OBJECTIVE

To understand the medical reasons for marijuana use, forms of marijuana used for medical purposes, and disclosure of use to physicians.

DESIGN

National, probability-based online survey.

SETTING

The USA, 2017.

PARTICIPANTS

16,280 US adults.

MAIN MEASURE

Proportion of US adults who agreed with a statement.

KEY RESULTS

A total of 9003 participants completed the survey (55% response rate). Five hundred ninety-one (7% of US adults) reported using marijuana for medical purposes. The most common medical reasons for marijuana use were anxiety (49%), insomnia (47%), chronic pain (42%), and depression (39%). The most common forms of use for all medical conditions were smoking and edibles, followed by vaping, concentrate, and topical. We found women were more likely to use marijuana for posttraumatic stress disorder, sleep, anxiety, and migraines. We did not find substantial variation in medical reasons for marijuana use by race. Among those using marijuana for medical purposes, 21% did not have a doctor. Among those with doctors, 33% did not inform them, 28% reported their doctor was neutral on their use, 32% reported their doctor was supportive, and 8% reported their doctor was not supportive. Those who lived in states where medical marijuana was illegal were less likely to disclose use to their doctor.

LIMITATION

The online format of the survey may have caused selection bias. Wording of the questions may have affected interpretation. Doctors were not queried directly, rather participants were asked about their perception of doctor attitudes.

CONCLUSION

Americans are using marijuana to treat medical conditions despite lack of evidence of efficacy.

Review of Medicinal Use of Cannabis Derivatives and the Societal Impact of Legalization

Background:

In recent past, there has been a rush to legalize marijuana along with a lot of support for its medicinal uses. This review intends to discuss the medicinal uses of marijuana and its adverse effects based on the current available evidence. Furthermore, it discusses the impact of legalization of marijuana.

Methodology:

This was a narrative review for which a thorough literature search was conducted on the Medline and PubMed databases. A detailed search of the Internet to find relevant information on webpages was also performed.

Results:

High-quality evidence for the majority of medical indications of marijuana remains investigational. Most of the available literature compares it against placebos. Postlegalization usage of marijuana has increased.

Conclusion:

It would be prudent to wait for studies which prove beyond doubt the advantages of marijuana over the existing drugs and also outweigh its side effects and addiction potential. Moreover, further legalization of marijuana should only be considered after evaluating its effects at places where it is already legally available.

Cannabinoids for fibromyalgia pain: a critical review of recent studies (2015-2019)

INTRODUCTION

Fibromyalgia is a chronic health condition characterized by widespread, severe musculoskeletal pain that affects an estimated 5-7% of the global population. Due to the highly comorbid nature of fibromyalgia, patients with the disorder often respond poorly to traditional pain treatments. Recent studies suggest that patient response may be more favorable to alternative analgesics, such as cannabis. However, the therapeutic potential of cannabis-based pain treatment for fibromyalgia remains unclear. The present study examined the most recent cannabis literature (2015-2019) and provides a critical review of current research on the safety and efficacy of medical cannabis treatments for fibromyalgia.

METHODS

We followed Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in searching the PubMed and Medline databases using the search terms "cannabis + fibromyalgia" and then "cannabinoids + fibromyalgia." Inclusion criteria were a) English language, b) published in peer review journals, c) published from 2015 to 2019, d) all study designs except for systematic reviews and meta-analyses, and e) all cannabis preparations.

RESULTS

The search identified five applicable studies involving 827 participants that used six different treatments. Review suggested several methodological problems pertaining to generalizability and validity.

CONCLUSION

Although the critically reviewed studies superficially suggest that medical cannabis is a safe and effective treatment for fibromyalgia pain, serious methodological limitations prevent a definitive conclusion regarding the use of cannabinoids for pain management in fibromyalgia patients at this time.

Canadian Guidelines on Cannabis Use Disorder Among Older Adults

Background

Cannabis Use Disorder (CUD) is an emerging and diverse challenge among older adults.

Methods

The Canadian Coalition for Seniors' Mental Health, with financial support from Health Canada, has produced evidence-based guidelines on the prevention, identification, assessment, and treatment of this form of substance use disorder.

Conclusions

Older adults may develop CUD in the setting of recreational and even medical use. Clinicians should remain vigilant for the detection of CUD, and they should be aware of strategies for prevention and managing its emergence and consequences The full version of these guidelines can be accessed at www.ccsmh.ca.

Cannabis-based medicines for chronic pain management: current and future prospects

PURPOSE OF REVIEW

The medicinal use of cannabis has recently become the focus of much medical, as well as political, attention. This reality of growing use but limited evidence creates unique dilemmas for the prescribing clinician. The purpose of this review is to explore current evidence and gaps in knowledge and offer some practical considerations.

RECENT FINDINGS

There is robust preclinical data regarding the relevance of the endocannabinoid system to many pain-relevant processes. However, evidence to support cannabis-based medicines clinical use is still lacking. The best evidence to date is in managing neuropathic pain, although whether effects are clinically significant remains undetermined. However, the safety profile of cannabinoids seems favorable, especially by comparison to other medications used for pain control.

SUMMARY

The endocannabinoid system is undoubtedly a new and exciting pharmaceutical target for chronic pain management, but transition from preclinical to clinical studies has so far proved difficult. Although it is reasonable to consider cannabinoids for otherwise unresponsive pain, care should be taken in frail clinical populations. As this has become a socioeconomic and political issue in which agendas often take precedence over due diligence, there is a pressing need for unbiased empirical data and high quality evidence to better inform prescribers and patients.

The effects of marijuana smoking on lung function in older people

BACKGROUND

Previous studies have associated marijuana exposure with increased respiratory symptoms and chronic bronchitis among long-term cannabis smokers. The long-term effects of smoked marijuana on lung function remain unclear.

METHODS

We determined the association of marijuana smoking with the risk of spirometrically defined chronic obstructive pulmonary disease (COPD) (post-bronchodilator forced expiratory volume in 1 s (FEV₁)/forced vital capacity ratio <0.7) in 5291 population-based individuals and the rate of decline in FEV₁ in a subset of 1285 males and females, aged ≥40 years, who self-reported use (or non-use) of marijuana and tobacco cigarettes and performed spirometry before and after inhaled bronchodilator on multiple occasions. Analysis for the decline in FEV₁ was performed using random mixed effects regression models adjusted for age, sex and body mass index. Heavy tobacco smoking and marijunana smoking was defined as >20 pack-years and >20 joint-years, respectively.

RESULTS

∼20% of participants had been or were current marijuana smokers with most having smoked tobacco cigarettes in addition (83%). Among heavy marijuana users, the risk of COPD was significantly increased (adjusted OR 2.45, 95% CI 1.55-3.88). Compared to never-smokers of marijuana and tobacco, heavy marijuana smokers and heavy tobacco smokers experienced a faster decline in FEV₁ by 29.5 mL·year^-1 (p=0.0007) and 21.1 mL·year^-1 (p<0.0001), respectively. Those who smoked both substances experienced a decline of 32.31 mL·year^-1 (p<0.0001).

INTERPRETATION

Heavy marijuana smoking increases the risk of COPD and accelerates FEV₁ decline in concomitant tobacco smokers beyond that observed with tobacco alone.

Psychosocial and Pharmacological Interventions for the Treatment of Cannabis Use Disorder

(Reprinted with permission from Sabioni P and Le Foll B. Psychosocial and pharmacological interventions for the treatment of cannabis use disorder [version 1; referees: 3 approved]. F1000Research 2018, 7(F1000 Faculty Rev):173 (https://doi.org/10.12688/f1000research.11191.1)).

A longitudinal study of cannabis use increasing the use of asthma medication in young Norwegian adults

Background

A small number of studies have shown that the use of cannabis increases the risk of bronchial asthma. There is, however, a paucity of longitudinal studies which are able to control for known risk factors of bronchial asthma.

Methods

Survey data from a population-based longitudinal study encompassing 2602 young adults followed for 13 years were coupled with individual prescription data on asthma medication (β₂-adrenergic receptor agonists and glucocorticoids for inhalation) from the Norwegian national prescription database, which covers the entire Norwegian population. Current cannabis use, gender, age, years of education, body mass index (BMI; kg/m²) and current smoking were measured.

Results

Prescription of asthma medication was associated with female gender, self-reported earlier asthma and allergies, daily tobacco smoking and current cannabis use. In a model adjusting for gender, age, years of education, BMI, earlier self-reported asthma and allergies and current tobacco smoking the odds ratio for a current cannabis user to fill prescriptions for asthma medication was 1.71 (95% CI: 1.06–2.77; p = 0.028).

Conclusions

This suggests that cannabis is a risk factor for bronchial asthma or use of asthma medication even when known risk factors are taken into consideration. Intake of cannabis through smoking should be avoided in persons at risk.

Marijuana use in transplantation: A call for clarity

Transplant centers have varying policies for marijuana (MJ) use in donors, transplant candidates, and recipients. Rationales for these differences range from concerns for fungal complications, impaired adherence, and drug interactions. This paper reviews the current status of MJ policies and practices in transplant centers and results of a survey sent to the American Society of Transplantation (AST) membership by the Executive Committee of the AST Infectious Diseases Community of Practice.The purpose of the survey was to compare policies and concerns of MJ use to actual observed complications. Of the 3321 surveys sent, 225 members (8%) responded. Transplant centers varied in their approval processes, differing even in organ types within the same institutions. Furthermore, there was discordance among transplant centers in their perceived risks of marijuana use as opposed to complications actually observed. An increasing number of states continue to legalize medical and recreational MJ resulting in widespread availability. Further research is needed to assess the validity of concerns for complications of MJ use in potential donors and recipients. Ultimately, standardized guidelines should be established based on studies and evidence-based criteria to assist transplant programs in their policies around the use of cannabis in their donors and recipients.

The Relationship Between Tobacco and Cannabis Use: A Review

BACKGROUND

Based on the prevalence and health implications of tobacco and cannabis use, aiming to reduce their use, especially among youth, is a sound objective at both the individual and public health level. A proper understanding of the relationships between tobacco and cannabis use may help to achieve this goal.

OBJECTIVES

To review the relationships between tobacco and cannabis use.

METHODS

A selective review of the literature.

RESULTS

We present an overview of the motivations for tobacco and cannabis use, and their perceived harmfulness. The article then reviews the gateway theory, reverse gateway theory, route of administration theory, and common liability theory. We describe the link between co-use and dependence symptoms, and the substitution phenomenon between tobacco and cannabis use. Three forms of simultaneous use-mulling, blunt smoking, and chasing-and their impacts are explained. We summarize the impact of tobacco use on cannabis (and vice versa) treatment outcomes, and, finally, review new treatments that simultaneously target tobacco and cannabis dependence. Most of the literature reviewed here relates to substance use among adolescents and young adults.

CONCLUSIONS

The use of tobacco and cannabis-two of the most widely used substances around the world-are strongly intertwined in several respects. Both health professionals and researchers should have well-informed views on this issue to better evaluate, understand, inform, and provide care to their patients.

Human lung epithelial cells cultured in the presence of radon-emitting rock experience gene expression changes similar to those associated with tobacco smoke exposure

Radon is the second leading cause of lung cancer, after tobacco smoke. While tobacco smoke-induced carcinogenesis has been studied extensively, far less is known about radon-induced carcinogenesis, particularly in relation to the influence of radon on gene expression. The objectives of the work described herein were to (a) determine if and how exposure to low dose radon-emitting rock influences cells, at the gene expression level, and (b) compare any gene expression changes resulting from the exposure to radon-emitting rock with those induced by exposure to tobacco smoke. Any potential radiation-induced gene expression changes were also compared to those induced by exposure to cannabis smoke, a non-carcinogen at low doses, used here as a smoke exposure comparator. Human lung epithelial cells were exposed to radon-emitting rock, tobacco smoke or cannabis smoke, over months, and RNA-sequencing was carried out. We found that the rock-exposed cells experienced significant gene expression changes, particularly of the gene AKR1C3, and that these changes, over time, increasingly reflected those associated with exposure to tobacco, but not cannabis, smoke. We postulate that the early gene expression changes common to both the radiation and tobacco smoke exposures constitute a related - potentially pre-carcinogenic - response. Our findings suggest that the length of time a dividing population of cells is exposed to a constant low concentration of radon (with a potential cumulative absorbed dose) could be an important risk parameter for neoplastic transformation/carcinogenesis.

Cannabis Use Is Associated With Increased Risk of Post-Endoscopic Retrograde Cholangiopancreatography Pancreatitis: Analysis of the US Nationwide Inpatient Sample Database, 2004-2014

OBJECTIVE

The aim of this study was to investigate the impact of cannabis on post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP).

METHODS

The US Nationwide Inpatient Sample was queried to identify patients who underwent endoscopic retrograde cholangiopancreatography pancreatitis from 2004 to 2014. Cannabis use was identified by International Classification of Diseases, Ninth Edition codes, and patients in remission were excluded. Poisson regression models were used to derive adjusted incidence risk ratios (IRRs) for outcomes.

RESULTS

Among 37,712 patients with PEP, 0.4% had documented cannabis use disorder. From 2004 to 2014, the rate of PEP and cannabis use increased (8.9%-11.0% [P < 0.01] and 0.20%-0.70% [P < 0.01], respectively). Univariate analysis demonstrated cannabis was associated with increased risk of PEP (IRR, 1.70; 95% confidence interval [CI], 1.50-1.90; P < 0.01). On multivariate analysis, cannabis use was an independent predictor of PEP (IRR, 1.2; 95% CI, 1.1-1.4; P = 0.004). Cannabis was not associated with in-hospital death (IRR, 0.15; 95% CI, 0.02-1.04; P = 0.06) but was associated with shorter hospital stay (IRR, 0.96; 95% CI, 0.94-0.98; P < 0.001) and lower costs (IRR, 0.91; 95% CI, 0.91-0.92; P < 0.001).

CONCLUSIONS

Cannabis use was associated with an increase in PEP without significant increase in mortality.

Long-Term Stress and Concomitant Marijuana Smoke Exposure Affect Physiology, Behavior and Adult Hippocampal Neurogenesis

Marijuana is a widely used recreational drug with increasing legalization worldwide for medical purposes. Most experimental studies use either synthetic or plant-derived cannabinoids to investigate the effect of cannabinoids on anxiety and cognitive functions. The aim of this study was to mimic real life situations where young people smoke cannabis regularly to relax from everyday stress. Therefore, we exposed young adult male NMRI mice to daily stress and concomitant marijuana smoke for 2 months and investigated the consequences on physiology, behavior and adult hippocampal neurogenesis. Animals were restrained for 6-h/day for 5-days a week. During the stress, mice were exposed to cannabis smoke for 2 × 30 min/day. We burned 2 “joints” (2 × 0.8 g marijuana) per occasion in a whole body smoking chamber. Cannabinoid content of the smoke and urine samples was measured by HPLC and SFC-MS/MS. Body weight gain was recorded daily and we did unrestrained, whole body plethysmography to investigate pulmonary functions. The cognitive performance of the animals was evaluated by the novel object recognition and Y maze tests. Anxietyrelated spontaneous locomotor activity and self-grooming were assessed in the open field test (OFT). Adult neurogenesis was quantified post mortem in the hippocampal dentate gyrus. The proliferative activity of the precursor cells was detected by the use of the exogenous marker 5-bromo-20-deoxyuridine. Treatment effects on maturing neurons were studied by the examination of doublecortin-positive neurons. Both stress and cannabis exposure significantly reduced body weight gain. Cannabis smoke had no effect on pulmonary functions, but stress delayed the maturation of several lung functions. Neither stress, nor cannabis smoke affected the cognitive functioning of the animals. Results of the OFT revealed that cannabis had a mild anxiolytic effect and markedly increased self-grooming behavior. Stress blocked cell proliferation in the dentate gyrus, but cannabis had no effect on this parameter. Marijuana smoke however had a pronounced impact on doublecortin-positive neurons influencing their number, morphology and migration. In summary, we report here that long-term stress in combination with cannabis smoke exposure can alter several health-related measures, but the present experimental design could not reveal any interaction between these two treatment factors except for body weight gain.

Cannabis: A joint problem for patients and the dental profession

Cannabis is one of the most commonly abused drugs in the UK. The debate about its legality has grown in recent times but the health implication of cannabis use is an issue of today. It is a drug commonly described as being 'soft' but its use has profound effects on many of the body's systems, including the oral cavity. This is of particular importance to the dental clinician. This paper aims to discuss the oral implications of cannabis use and provide advice on ways in which dental professionals can approach this sensitive topic and provide support.