US researchers found it may cause changes in the epigenome, which acts like a set of switches that activate or deactivate genes involved in how our bodies function; findings that were validated by a systematic literature review published in 2024 by researchers in Portugal.
“We observed associations between cumulative marijuana use and multiple epigenetic markers across time,” epidemiologist Lifang Hou from Northwestern University explained of his team’s findings in 2023.
Cannabis is a commonly used substance in the US, with nearly half of Americans having tried it at least once, Hou and team report in their published paper.
To investigate this, the researchers analyzed data from a long-running health study that had tracked around 1,000 adults over two decades.
Participants, who were between 18 and 30 years old when the study began, were surveyed about their cannabis use over the years and gave blood samples at the 15- and 20-year marks.
Using these blood samples from five years apart, Hou and her team looked at the epigenetic changes, specifically DNA methylation levels, of people who had used cannabis recently or for a long time.
Without changing the genomic sequence, DNA methylation affects how easily cells ‘read’ and interpret genes, much like someone covering up key lines in your set of instructions.
“We previously identified associations between marijuana use and the aging process as captured through DNA methylation,” Hou said.
The comprehensive data on the participants’ cannabis use allowed the researchers to estimate cumulative use over time as well as recent use and compare it with DNA methylation markers in their blood for analysis.
They found numerous DNA methylation markers in the 15-year blood samples, 22 that were associated with recent use, and 31 associated with cumulative cannabis use.
In the samples taken at the 20-year point, they identified 132 markers linked to recent use and 16 linked to cumulative use.
“Interestingly, we consistently identified one marker that has previously been associated with tobacco use,” Hou explained, “suggesting a potential shared epigenetic regulation between tobacco and marijuana use.”
It’s important to note that this study doesn’t prove that cannabis directly causes these changes or causes health problems.
“This research has provided novel insights into the association between marijuana use and epigenetic factors,” said epidemiologist Drew Nannini from Northwestern University.
“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.”
Source: https://www.yahoo.com/news/articles/cannabis-linked-epigenetic-changes-scientists-215447890.html?