As we age, our cells experience chemical changes. One type of change occurs when a molecule called a methyl attaches to DNA. This methylation modifies the DNA, but doesn’t change its underlying chemical structure. However, it can turn off affected genes, or change how those genes work. Biologists refer to this as an epigenetic change.
Some DNA methylation markers are associated with marijuana use. Given the rise in marijuana legalization in the U.S., a group of researchers from Northwestern University, the University of Minnesota, and the University of California decided to check the association between epigenetic factors and recent and cumulative marijuana use. They performed tests in examination years 15 and 20 (Y15 and Y20) on middle-aged adults in the long-term Coronary Artery Risk Development in Young Adults Study. At each examination, they asked participants to assess their recent marijuana use, which the researchers then used to determine both recent and cumulative marijuana use.
At Y15 (n=1,023 participants), they identified 22 methylation markers for recent use, and 31 for cumulative use. At Y20 (n=883), the numbers were 132 and 16, respectively. They also identified 640 methylation variations in nearby genes, and 198 varying methylation patterns across the samples. These methylated genes proved much more common in gene pathways associated with cancer, infections, schizophrenia, bipolar disorder, and substance use disorders, suggesting that recent and cumulative marijuana use may trigger or contribute to all of the above.
Click here to read the Nature article detailing their results.