In a comparison of 100 participants across five smoking groups, cannabis users showed no significant increase in micronuclei (a marker of DNA damage) in cheek cells, unlike tobacco, reverse, and e-cigarette smokers.
Oral health researchers, toxicologists, smoking harm reduction advocates
Cannabis smoking P=0.89 vs non-smokers for DNA damage
What the researchers found
Among 100 participants (20 per group), micronuclei (markers of genotoxic damage) were present in 86% of all samples. Statistically significant increases in micronucleus count were observed for conventional tobacco, reverse smoking, and electronic cigarette users compared to non-smokers. Cannabis smokers showed no significant difference from non-smokers (P=0.89). A significant correlation existed between oral lesions and micronucleus count. Regression analysis ruled out alcohol as a confounding factor.
Why it matters
While smoking of any kind raises health concerns, this study suggests cannabis smoke may not produce the same genotoxic damage to oral tissue as tobacco smoke or e-cigarette vapor. This distinction matters for understanding the relative oral cancer risks of different smoking behaviors.
The numbers in context
n=100 (20 per group); 86% had micronuclei present; cannabis vs non-smokers P=0.89 (not significant); tobacco, reverse, and e-cigarette smokers all significantly elevated; alcohol ruled out as confounder
How the study worked
Cross-sectional study with 100 participants in five groups: conventional tobacco (n=20), reverse smokers (n=20), e-cigarette users (n=20), cannabis users (n=20), and non-smokers (n=20). Exfoliated buccal mucosa cells analyzed using Giemsa and Papanicolaou staining for micronuclei.
What this study cannot tell us
Very small sample (20 per group). Cross-sectional design cannot assess cumulative exposure effects. Micronucleus assay captures one form of DNA damage but not all. Cannabis and tobacco smoking frequency, duration, and co-use patterns were not fully characterized.
How to read the evidence
Small sample size (20 per group) and single-measure cross-sectional design provide preliminary evidence only, despite the clear finding of no significant difference.
When this study was published
2025 publication
The bigger picture
The assumption that all smoked substances are equally harmful to oral tissues may not hold. This finding, while preliminary, suggests that the genotoxic risk profile of cannabis smoke differs from tobacco smoke, which has implications for risk communication and harm reduction strategies.
Questions still open
- Does long-term heavy cannabis smoking eventually produce oral genotoxic damage? Are there other forms of DNA damage not captured by the micronucleus assay that cannabis smoke might cause?
Common questions
What are micronuclei?
Does this mean cannabis smoking is safe for oral health?
Read the original research
Genotoxic damage assessment using the micronucleus assay in buccal mucosa of different types of smokers: A cross-sectional study.
World journal of experimental medicine, 15(3), 108025
Citation
Álvarez-Martínez, Efraín; Porto-Puerta, Iván E; Ardila, Carlos M. (2025). Genotoxic damage assessment using the micronucleus assay in buccal mucosa of different types of smokers: A cross-sectional study.. World journal of experimental medicine, 15(3), 108025. https://doi.org/10.5493/wjem.v15.i3.108025