A recent study of over 1,000 adults has revealed that cannabis use may lead to changes in the human body’s epigenome. The epigenome acts as a set of switches, capable of activating or deactivating genes, thereby altering how our bodies function. The study, spearheaded by Lifang Hou, a medical doctor and epidemiologist from Northwestern University Feinberg School of Medicine, shed light on the association between marijuana use and multiple epigenetic markers over time. Published in July 2023, this research brings attention to the growing prevalence of cannabis use in the United States and the need for a better understanding of its effects on our health.
Cannabis, commonly used in the United States, has seen 49 percent of the population experiment with the substance at some point in their lives. Although certain states and countries have legalized its use, the full extent of its impact on human health remains unknown. To further investigate this, Hou and her team focused on a sample of approximately 1,000 adults who had previously participated in a long-term study spanning two decades. In this study, participants were questioned about their cannabis use over the course of 20 years. Multiple blood samples were collected, the first at the 15-year mark, followed by another at the 20-year mark. The participants, aged between 18 and 30 at baseline, were perfect candidates for investigating epigenetic changes related to cannabis usage.
DNA methylation, one of the most extensively studied epigenetic modifications, involves the addition or removal of methyl groups from DNA. This process alters the activity of genes without modifying the genomic sequence. These changes can impede the cells’ ability to interpret the genetic instructions accurately. Numerous environmental and lifestyle factors, including drug use, can trigger DNA methylation changes that may be passed on to future generations. To understand the relationship between cannabis use and epigenetic factors, Hou and her team analyzed the DNA methylation levels in blood samples taken five years apart from individuals who had either recently or chronically used cannabis.
Hou and her team were able to estimate the participants’ cumulative cannabis use over time, as well as recent use, based on comprehensive data collected during the long-term study. The researchers then compared this cumulative and recent use of cannabis with DNA methylation markers found in the blood samples. They discovered a considerable number of methylation markers in the 15-year blood samples, with 22 markers associated with recent use and 31 markers associated with cumulative use. Furthermore, in the 20-year blood samples, the team identified 132 markers linked to recent use and 16 markers linked to cumulative use. Interestingly, they also observed one marker commonly associated with tobacco use, indicating a potential shared epigenetic regulation between marijuana and tobacco use.
Previous research has linked multiple epigenetic changes associated with cannabis use to various health outcomes, such as cellular proliferation, hormone signaling, infections, and neurological disorders like schizophrenia and bipolar disorder. It’s important to note, however, that this study does not establish a direct causal relationship between cannabis use, epigenetic changes, and health problems. Drew Nannini, an epidemiologist from Northwestern University, emphasized the significance of this research in providing new insights into the association between marijuana use and epigenetic factors. Nannini also stresses the need for additional studies to validate these findings across different populations.
This groundbreaking study sheds light on the potential influence of cannabis use on the human epigenome. By examining the correlations between marijuana consumption and DNA methylation markers, researchers have uncovered valuable insights into the impact of cannabis on our bodies. While these findings contribute to our understanding of the association between cannabis use and epigenetic changes, further research is necessary to fully comprehend the broader implications and establish definitive cause-and-effect relationships.