Sharing cannabis bongs linked to 4x higher tuberculosis risk in Thailand | Research

The takeaway

In a Thai case-control study, smoking and sharing a bong of cannabis was associated with a 4.2-fold higher odds of active pulmonary tuberculosis, with a population-attributable fraction similar to tobacco smoking.

People interested in harm reduction for cannabis use, particularly respiratory risks from sharing smoking devices.

4.2x higher TB odds from sharing cannabis bongs

What the researchers found

After adjusting for covariates, smoking and sharing a cannabis bong had an odds ratio of 4.22 (95% CI: 1.47-12.07) for TB. No significant association was found for other types of cannabis consumption. The population-attributable fraction for shared cannabis bongs was 12.16%, compared to 12.62% for tobacco smoking.

Why it matters

In TB-endemic countries, sharing smoking devices is a plausible transmission route. This study isolates shared cannabis bong use as a specific risk behavior, distinct from cannabis use in general, which has direct implications for harm reduction messaging.

The numbers in context

148 TB cases, 117 controls. 11% of controls were current cannabis users. 19% had ever used. Shared bong OR: 4.22 (95% CI: 1.47-12.07). PAF: 12.16% for shared bongs vs. 12.62% for tobacco. Other cannabis consumption types: not significant.

How the study worked

Matched case-control study in Songkhla Province, Thailand (2023). 148 TB cases and 117 healthy controls completed face-to-face interviews about cannabis consumption. Multivariate logistic regression estimated odds ratios. Population-attributable fractions calculated.

What this study cannot tell us

Small sample size from one Thai province. Case-control design limits causal inference. Self-reported cannabis use may be inaccurate. Cannot separate the effect of sharing from the effect of bong smoking itself. Cultural context (Thai waterpipe sharing) may not generalize.

How to read the evidence

Case-control study with face-to-face interviews and adjusted analysis. Limited by small sample, single province, and inability to separate device-sharing risk from smoking risk.

When this study was published

Published in 2024 with data collected in 2023 from Southern Thailand.

The bigger picture

Following Thailand cannabis legalization in 2022, understanding which specific behaviors carry health risks is critical for targeted harm reduction. This study suggests the TB risk is about sharing the device, not necessarily about cannabis use itself.

Questions still open

Would harm reduction messaging about not sharing smoking devices reduce TB transmission? Is the risk specific to waterpipes/bongs, or would sharing joints carry similar risk? Does this finding apply in lower TB-prevalence countries?

Common questions

Can sharing cannabis increase TB risk?

This study found that specifically sharing a cannabis bong was associated with 4.2 times higher tuberculosis risk. Other forms of cannabis consumption were not significantly associated, suggesting the sharing behavior, not cannabis itself, is the risk factor.

How does this compare to tobacco as a TB risk factor?

The population-level impact was nearly identical: shared cannabis bongs accounted for an estimated 12.2% of TB cases versus 12.6% for tobacco smoking, making them comparably important risk factors in this Thai population.

Read the original research

Increased active pulmonary tuberculosis risk from sharing bong of cannabis: a case-control study from Thailand.

Frontiers in public health, 12, 1474761

View on PubMed ↗Publisher’s paper ↗

Citation

Chumchuen, Kemmapon; Chongsuvivatwong, Virasakdi. (2024). Increased active pulmonary tuberculosis risk from sharing bong of cannabis: a case-control study from Thailand.. Frontiers in public health, 12, 1474761. https://doi.org/10.3389/fpubh.2024.1474761