A study of over 1,000 adults suggests that using cannabis may lead to changes in the human body’s epigenome. The epigenome functions like a set of switches, activating or deactivating genes to change how our bodies function.
Lifang Hou, a preventive medical doctor and epidemiologist from Northwestern University Feinberg School of Medicine, explained in July 2023 that they observed associations between cumulative marijuana use and multiple epigenetic markers across time.
Cannabis is a commonly used substance in the United States, with 49 percent of people trying it at least once. Some US states and other countries have made it legal, but we still don’t fully understand its effects on our health, as reported by Hou and a team of US researchers in their published paper.
The researchers studied around 1,000 adults who had participated in a long-term previous study where they had been asked about their cannabis use over a 20-year period. Using blood samples from five years apart, Hou and her team looked at the epigenetic changes, specifically DNA methylation levels, of people who had recently used cannabis or used it for a long time.
The addition or removal of methyl groups from DNA is one of the most studied epigenetic modifications. Environmental and lifestyle factors can trigger these methylation changes, and blood biomarkers can provide information about both recent and historical exposures.
“We previously identified associations between marijuana use and the aging process as captured through DNA methylation,” Hou said, adding that they wanted to further explore whether specific epigenetic factors were associated with marijuana and whether these factors are related to health outcomes.
“The comprehensive data on the participants cannabis use allowed them to estimate cumulative use over time as well as recent use and compare it with DNA methylation markers in their blood for analysis,” Hou explained
They found numerous DNA methylation markers associated with recent and cumulative cannabis use, some of which were linked to tobacco use, suggesting a potential shared epigenetic regulation between tobacco and marijuana use.
Multiple epigenetic changes associated with cannabis use had previously been linked to various health conditions, but it’s important to note that this study doesn’t prove that cannabis directly causes these changes or health problems.
“This research has provided novel insights into the association between marijuana use and epigenetic factors,” said epidemiologist Drew Nannini from Northwestern University, adding, “Additional studies are needed to determine whether these associations are consistently observed in different populations and to examine the effect of marijuana on age-related health outcomes.”
The study has been published in Molecular Psychiatry, with an earlier version of this article being published in July 2023.
