Cannabis use and the risk of tuberculosis: a systematic review

Relationship between hospitalization from cannabis usage and pulmonary tuberculosis in Thailand from 2017 to 2022

In June 2022, Thailand legalized recreational cannabis. Currently, cannabis is now the most consumed drug. Cannabis usage can increase inflammatory responses in the respiratory tract. Sharing of cannabis waterpipes has been linked to increased tuberculosis risks. Using a national in-patient databank, we aimed to 1) describe the spatiotemporal correlation between cannabis-related and tuberculosis hospital admissions, and 2) compare the rate of subsequent pulmonary tuberculosis admission between those with prior admissions for cannabis-related causes and those without. Both admission types were aggregated to the number of admissions in monthly and provincial units. Temporal and spatial patterns were visualized using line plots and choropleth maps, respectively. A matched cohort analysis was conducted to compare the incidence density rate of subsequent tuberculosis admission and the hazard ratio. Throughout 2017-2022, we observed a gradual decline in tuberculosis admissions, in contrast to the increase in cannabis-related admissions. Both admissions shared a hotspot in Northeastern Thailand. Between matched cohorts of 6,773 in-patients, the incidence density rate per 100,000 person-years of subsequent tuberculosis admissions was 267.6 and 165.9 in in-patients with and without past cannabis-admission, respectively. After adjusting for covariates, we found that a cannabis-related admission history was associated with a hazard ratio of 1.48 (P = 0.268) for subsequent tuberculosis admission. Our findings failed to support the evidence that cannabis consumption increased pulmonary tuberculosis risk. Other study types are needed to further assess the association between cannabis consumption and pulmonary tuberculosis.

The impact of alcohol and illicit substance use on the pharmacokinetics of first-line TB drugs

BACKGROUND

In South Africa, an estimated 11% of the population have high alcohol use, a major risk factor for TB. Alcohol and other substance use are also associated with poor treatment response, with a potential mechanism being altered TB drug pharmacokinetics.

OBJECTIVES

To investigate the impact of alcohol and illicit substance use on the pharmacokinetics of first-line TB drugs in participants with pulmonary TB.

METHODS

We prospectively enrolled participants ≥15 years old, without HIV, and initiating drug-susceptible TB treatment in Worcester, South Africa. Alcohol use was measured via self-report and blood biomarkers. Other illicit substances were captured through a urine drug test. Plasma samples were drawn 1 month into treatment pre-dose, and 1.5, 3, 5 and 8 h post-dose. Non-linear mixed-effects modelling was used to describe the pharmacokinetics of rifampicin, isoniazid, pyrazinamide and ethambutol. Alcohol and drug use were tested as covariates.

RESULTS

The study included 104 participants, of whom 70% were male, with a median age of 37 years (IQR 27-48). Alcohol use was high, with 42% and 28% of participants having moderate and high alcohol use, respectively. Rifampicin and isoniazid had slightly lower pharmacokinetics compared with previous reports, whereas pyrazinamide and ethambutol were consistent. No significant alcohol use effect was detected, other than 13% higher ethambutol clearance in participants with high alcohol use. Methaqualone use reduced rifampicin bioavailability by 19%.

CONCLUSION

No clinically relevant effect of alcohol use was observed on the pharmacokinetics of first-line TB drugs, suggesting that poor treatment outcome is unlikely due to pharmacokinetic alterations. That methaqualone reduced rifampicin means dose adjustment may be beneficial.

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.

Smoked drug use in patients with TB is associated with higher bacterial burden

BACKGROUND: Smoking of illicit drugs may lead to more rapid TB disease progression or late treatment presentation, yet research on this topic is scant. We examined the association between smoked drug use and bacterial burden among patients newly initiated on drug-susceptible TB (DS-TB) therapy.METHODS: Data from 303 participants initiating DS-TB treatment in the Western Cape Province, South Africa, were analyzed. Smoked drug use was defined as self-reported or biologically verified methamphetamine, methaqualone and/or cannabis use. Proportional hazard and logistic regression models (adjusted for age, sex, HIV status and tobacco use) examined associations between smoked drug use and mycobacterial time to culture positivity (TTP), acid-fast bacilli sputum smear positivity and lung cavitation.RESULTS: People who smoked drugs (PWSD) comprised 54.8% (n = 166) of the cohort. TTP was faster for PWSD (hazard ratio 1.48, 95% CI 1.10-1.97; P = 0.008). Smear positivity was higher among PWSD (OR 2.28, 95% CI 1.22-4.34; P = 0.011). Smoked drug use (OR 1.08, 95% CI 0.62-1.87; P = 0.799) was not associated with increased cavitation.CONCLUSIONS: PWSD had a higher bacterial burden at diagnosis than those who do not smoke drugs. Screening for TB among PWSD in the community may facilitate earlier linkage to TB treatment and reduce community transmission.

Tobacco smoking and meningococcal disease in adolescents and young adults: a systematic review and meta-analysis

OBJECTIVES

Systematically review the evidence on the association between active and passive tobacco smoking and invasive meningococcal disease (IMD) in adolescents and young adults aged 15-to-24-years.

METHODS

Electronic searches were conducted in Ovid MEDLINE, EMBASE, and Web of Science to June 2020. Reference lists were hand-searched. Two independent reviewers screened articles for eligibility. Risk of bias was assessed using an adapted Risk of Bias in Non-Randomised Studies - of Interventions tool. Meta-analyses were conducted using random-effects models.

RESULTS

Of 312 records identified, 13 studies were included. Five studies provided data on the association between active smoking and IMD in the target age group; pooled odds ratio (OR): 1.45 (95% CI: 0.93-2.26). The overall OR, including eight studies with a wider participant age range, was 1.45 (95% CI: 1.12-1.88). For passive smoking, the equivalent ORs were 1.56 (95% CI: 1.09-2.25) and 1.30 (95% CI: 1.06-1.59) respectively. All studies were at high risk of bias.

CONCLUSIONS

Active and passive smoking may be associated with IMD in adolescents and young adults. Since active smoking has also been linked to meningococcal carriage, and passive smoking to IMD in young children, smoking cessation should be encouraged to reduce transmission and IMD risk in all ages.