Cannabis Smoking Was Linked to Higher Risk of Nasopharyngeal Cancer in North Africa
Marijuana smoking significantly elevated nasopharyngeal carcinoma risk independently of cigarette smoking in a large North African case-control study, suggesting different cancer-causing mechanisms between cannabis and tobacco.
Quick Facts
What This Study Found
Researchers interviewed 636 nasopharyngeal carcinoma (NPC) patients and 615 matched controls across Algeria, Morocco, and Tunisia.
Cigarette smoking and snuff were associated with differentiated NPC but not with undifferentiated carcinoma (UCNT), the dominant type in these populations.
Marijuana smoking significantly elevated NPC risk independently of cigarette smoking. Statistical analyses (stratified permutation test and conditional logistic regression) confirmed this was an independent effect, suggesting cannabis and tobacco may cause cancer through different mechanisms.
Domestic cooking fumes from charcoal ovens during childhood also increased risk. Neither alcohol nor water pipe smoking was associated with NPC.
Key Numbers
636 NPC patients and 615 controls from Algeria, Morocco, and Tunisia. Cannabis effect was independent of cigarette smoking. Childhood cooking fume exposure (from charcoal ovens) also elevated risk.
How They Did This
This case-control study enrolled 636 NPC patients and 615 controls from three North African countries (2002-2005), frequency-matched by center, age, sex, and childhood household type. Conditional logistic regression evaluated lifestyle associations with NPC risk, controlling for socioeconomic status and dietary factors.
Why This Research Matters
This was one of the first studies to identify cannabis as an independent risk factor for a specific cancer type in a large population, separate from tobacco effects.
The Bigger Picture
The cancer risks of cannabis smoke remain debated. This study provided population-level evidence for one specific cancer type, though nasopharyngeal carcinoma is relatively rare and has unique risk factors including Epstein-Barr virus exposure.
What This Study Doesn't Tell Us
Case-control design relies on participants accurately recalling past cannabis use. North African cannabis use patterns (kif smoking) may differ from patterns in other regions. NPC is a relatively uncommon cancer with specific regional risk factors that may not apply broadly.
Questions This Raises
- ?What specific compounds in cannabis smoke contribute to NPC risk?
- ?Does the independent effect suggest a different carcinogenic pathway than tobacco?
- ?Would these findings apply to non-smoked cannabis products?
Trust & Context
- Key Stat:
- Cannabis independently elevated NPC risk in 1,251 participants across three countries
- Evidence Grade:
- Large multi-country case-control study with appropriate matching and statistical controls, though retrospective design introduces recall bias.
- Study Age:
- Published in 2009. The relationship between cannabis smoking and head/neck cancers has continued to be studied with mixed results in different populations.
- Original Title:
- Cannabis, tobacco and domestic fumes intake are associated with nasopharyngeal carcinoma in North Africa.
- Published In:
- British journal of cancer, 101(7), 1207-12 (2009)
- Authors:
- Feng, B-J, Khyatti, M, Ben-Ayoub, W, Dahmoul, S, Ayad, M, Maachi, F, Bedadra, W, Abdoun, M, Mesli, S, Bakkali, H, Jalbout, M, Hamdi-Cherif, M, Boualga, K, Bouaouina, N, Chouchane, L, Benider, A, Ben-Ayed, F, Goldgar, D E, Corbex, M
- Database ID:
- RTHC-00352
Evidence Hierarchy
Compares people with a condition to similar people without it.
What do these levels mean? →Frequently Asked Questions
Does cannabis cause cancer?
This study found cannabis smoking was associated with one specific cancer type (nasopharyngeal carcinoma) in North Africa. It does not establish that cannabis causes cancer broadly, but it does suggest combusted cannabis may carry independent cancer risks for certain tissues.
Is the risk from smoking specifically, or from cannabis itself?
The study examined smoked cannabis. The carcinogenic risk likely comes from combustion products rather than cannabinoids themselves, which is why route of administration matters for risk assessment.
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Cite This Study
https://rethinkthc.com/research/RTHC-00352APA
Feng, B-J; Khyatti, M; Ben-Ayoub, W; Dahmoul, S; Ayad, M; Maachi, F; Bedadra, W; Abdoun, M; Mesli, S; Bakkali, H; Jalbout, M; Hamdi-Cherif, M; Boualga, K; Bouaouina, N; Chouchane, L; Benider, A; Ben-Ayed, F; Goldgar, D E; Corbex, M. (2009). Cannabis, tobacco and domestic fumes intake are associated with nasopharyngeal carcinoma in North Africa.. British journal of cancer, 101(7), 1207-12. https://doi.org/10.1038/sj.bjc.6605281
MLA
Feng, B-J, et al. "Cannabis, tobacco and domestic fumes intake are associated with nasopharyngeal carcinoma in North Africa.." British journal of cancer, 2009. https://doi.org/10.1038/sj.bjc.6605281
RethinkTHC
RethinkTHC Research Database. "Cannabis, tobacco and domestic fumes intake are associated w..." RTHC-00352. Retrieved from https://rethinkthc.com/research/feng-2009-cannabis-tobacco-and-domestic
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.