Cannabis smoking is associated with advanced epigenetic age

Cannabis use has been controversial, largely having been designated a controlled substance over the last century. The link between cannabis smoking and disease pathogenesis may best be explored through DNA methylation, an epigentic mechanism. We investigated the relationship between epigenetic age and cannabis smoking in participants within the Canadian Cohort of Obstructive Lung Disease (CanCOLD) cohort (n=93) (ClinicalTrials.gov identifier NCT00920348). Blood samples were profiled for DNA methylation using the Illumina MethylationEPIC BeadChipv1 at two separate laboratories and the blood epigenetic age of each sample was calculated using the Clock Foundation tool (https://dnamage.clockfoundation.org). An ANOVA was used to identify differences in the age acceleration residuals associated with cannabis smoking status (never, former, and current), adjusted for chronological age, sex, body mass index (BMI), batch, cigarette smoking status, and the first two principal components of blood cell proportions. Our observations indicated that current cannabis smoking and higher joint-years exposure are associated with epigenetic age acceleration; cessation, however, may help to normalize in part this age acceleration. 93 samples profiles for blood DNA methyaltion contributor:CanCOLD Collaborative Research Group