Marijuana (Cannabis) Smoking Increases the Risk of Lung Cancer: Evidence from a Systematic Review and Meta-Analysis

Document Type : Review Article(s)

Authors

1 Faculty of Medicine, Bogomolets National Medical University (NMU), Kyiv, Ukraine

2 Department of Food Science and Technology, Ayatollah Amoli Branch, Islamic Azad University, Amol, Iran

3 Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran

4 Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran

5 Cancer Research Center, Shahid Beheshti University of Medical Sciences (SBUMS), Tehran, Iran

10.34172/ahj.1710

Abstract

Introduction: Marijuana (cannabis) use has become increasingly prevalent worldwide, raising concerns about its potential long-term health effects, particularly on the respiratory system. While tobacco smoking is a well-established risk factor for lung cancer, the association between cannabis use and lung cancer risk remains unclear and controversial. This systematic review and meta-analysis of existing observational studies aimed to evaluate the potential relationship between marijuana use and the risk of developing lung cancer.
Methods: A systematic search was conducted across PubMed, Web of Science, and Scopus to identify cohort and case-control studies up to September 2025. Studies were selected, relevant data were extracted, and statistically analyzed using effect sizes (ES) and 95% confidence intervals (CI). All analyses were conducted using STATA software.
Findings: This meta-analysis included six observational studies, comprising 16 effect sizes, consisting of two cohort studies and four case-control studies. The pooled analysis of the cohort studies (7 effect sizes) indicated a statistically significant association between marijuana (cannabis) smoking and increased lung cancer risk (ES: 2.06; 95% CI: [1.04–4.07]; P = 0.038; I² = 75%). In contrast, the meta-analysis of the case-control studies (9 effect sizes) showed a non-significant increase in risk (ES: 1.16; 95% CI: [0.71–1.88]; P = 0.542; I² = 82%).
Conclusion: This meta-analysis indicates that marijuana smoking may increase lung cancer risk, with cohort studies showing a significant twofold association. Although case-control studies were not statistically significant, the upward trend highlights the importance of considering cannabis use in lung cancer risk assessments and patient counseling.

Highlights

Mehdi Karimi(GoogleScholar)(Pubmed)

Keywords

References

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Addiction & Health
Volume 18
Pages 1-8

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