Changes in the human epigenome (epigenetic changes) are linked with marijuana use. The study was published in Molecular Psychiatry.
CDC says that Marijuana is used very commonly in the US. Approximately 48.2 million people (18% Americans) have used it at least once in 2019, the most recent available data. Moreover, the senior author of the study Lifang Hou, MD, Ph.D., said that marijuana is legalized in most states. But the consequences of the drug on health are not understood.
Hou said,
Despite its growing popularity, as well as recent legalization by several states, the effect of marijuana on epigenetic factors has not been well studied
We previously identified associations between marijuana use and the aging process as captured through DNA methylation. We wanted to further explore whether specific epigenetic factors were associated with marijuana and whether these factors are related to health outcomes.
Analysis of the Study
Investigators of the study analyzed the blood samples of people who participated in CARDIA (Coronary Artery Risk Development in Young Adults) that were drawn five years apart. The current study comprised data from more than 900 adults. Every participant went under a survey for recent use of marijuana and estimated combined use. After which a DNA methylation profiling of the blood samples was done to reveal epigenetic changes in association with marijuana use.
Scientists could link the use of marijuana and changes in human epigenome by studying the changes in DNA methylation. The investigators observed 21 and 31 DNA methylation markers in association with recent and combined marijuana use from the first samples. Moreover, 132 and 16 methylation markers were used in the second batch of samples.
Hou said multiple epigenetic changes had been found in pathways linked with cellular proliferation, infections, hormone signalling, and mental health disorders.
Hou added,
In our study, we observed associations between cumulative marijuana use and multiple epigenetic markers across time,
Interestingly, we consistently identified one marker that has previously been associated with tobacco use, suggesting a potential shared epigenetic regulation between tobacco and marijuana use. The observed marijuana markers were also associated with cell proliferation, infection and psychiatric disorders, however, additional studies are needed to replicate and verify these findings.
The study however does not establish a casual relationship between epigenetic changes and marijuana. Nor does it form one between observed health outcomes and epigenetic changes. But the findings can be useful for further research on epigenetic changes.
Nannini said,
This research has provided novel insights into the association between marijuana use and epigenetic factors
Additional studies are needed to determine whether these associations are consistently observed in different populations. Moreover, studies examining the effect of marijuana on age-related health outcomes may provide further insight into the long-term effect of marijuana on health.