Alcohol and tobacco changed thousands of DNA methylation sites, but marijuana showed no significant effects
In a cohort of 3,424 adults, alcohol drinking altered 2,569 DNA methylation sites and tobacco smoking altered 528, but marijuana consumption showed no significant methylation changes after correcting for multiple comparisons.
Quick Facts
What This Study Found
Three epigenome-wide association studies in the same cohort found 2,569 CpG sites differentially methylated by alcohol and 528 by tobacco. Marijuana showed no significant associations after multiple comparison correction. Sixty-one genes overlapped between alcohol and tobacco, enriched in nervous and cardiovascular system processes. Sixty-six CpG sites mediated alcohol's effect on hypertension, with the top site (SLC7A11) mediating 70.5% of the effect.
Key Numbers
3,424 participants; 2,569 CpG sites for alcohol; 528 for tobacco; 0 significant for marijuana; 61 overlapping genes; 66 CpG sites mediated alcohol-hypertension link; SLC7A11 mediated 70.5% of alcohol's hypertension effect (P=0.006)
How They Did This
Epigenome-wide association studies using the Infinium EPIC BeadChip in whole blood from 3,424 participants. Assessed effects of tobacco, alcohol, and marijuana on DNA methylation, followed by mediation analysis for hypertension.
Why This Research Matters
This is one of the first studies to compare epigenetic effects of all three substances in the same cohort, providing an important null result for marijuana while revealing that alcohol may drive hypertension largely through DNA methylation changes.
The Bigger Picture
The finding that alcohol and tobacco produce extensive epigenetic changes while marijuana does not provides molecular-level context for the relative health impacts of these three commonly used substances.
What This Study Doesn't Tell Us
Cross-sectional design cannot establish temporal relationships. Marijuana use may have been less prevalent or at lower levels than alcohol/tobacco in this cohort. Blood-based methylation may not reflect tissue-specific effects. Multiple comparison correction may have been overly conservative for marijuana given lower statistical power.
Questions This Raises
- ?Would higher-dose or longer-duration marijuana use produce detectable methylation changes?
- ?Are the null marijuana findings due to truly no effect or insufficient power?
Trust & Context
- Key Stat:
- Marijuana: 0 significant methylation changes vs. 2,569 for alcohol
- Evidence Grade:
- Well-powered epigenome-wide study using validated methylation array in a single cohort, though cross-sectional design and potential power limitations for marijuana analysis are caveats.
- Study Age:
- Published 2023
- Original Title:
- Impact of tobacco, alcohol, and marijuana on genome-wide DNA methylation and its relationship with hypertension.
- Published In:
- Epigenetics, 18(1), 2214392 (2023)
- Authors:
- Carreras-Gallo, Natàlia, Dwaraka, Varun B, Cáceres, Alejandro, Smith, Ryan, Mendez, Tavis L, Went, Hannah, Gonzalez, Juan R
- Database ID:
- RTHC-04451
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
Does marijuana change DNA methylation like alcohol and tobacco do?
In this study of 3,424 adults, alcohol altered 2,569 DNA sites and tobacco 528, but marijuana showed no significant changes after statistical correction, suggesting a different epigenetic impact profile.
How does alcohol affect hypertension through DNA changes?
The study found 66 DNA methylation sites that mediated alcohol's effect on hypertension, with the top site in the SLC7A11 gene accounting for 70.5% of alcohol's contribution to hypertension risk.
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Cite This Study
https://rethinkthc.com/research/RTHC-04451APA
Carreras-Gallo, Natàlia; Dwaraka, Varun B; Cáceres, Alejandro; Smith, Ryan; Mendez, Tavis L; Went, Hannah; Gonzalez, Juan R. (2023). Impact of tobacco, alcohol, and marijuana on genome-wide DNA methylation and its relationship with hypertension.. Epigenetics, 18(1), 2214392. https://doi.org/10.1080/15592294.2023.2214392
MLA
Carreras-Gallo, Natàlia, et al. "Impact of tobacco, alcohol, and marijuana on genome-wide DNA methylation and its relationship with hypertension.." Epigenetics, 2023. https://doi.org/10.1080/15592294.2023.2214392
RethinkTHC
RethinkTHC Research Database. "Impact of tobacco, alcohol, and marijuana on genome-wide DNA..." RTHC-04451. Retrieved from https://rethinkthc.com/research/carreras-gallo-2023-impact-of-tobacco-alcohol
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.