24 Night shift work and epigenetic modifications: miRNA relative expression levels among a European cohort of night shift workers

Objective To date, the major pathways contributing to cardiovascular disease among night shift workers remain poorly understood. MicroRNAs (miRNAs) have been identified as novel regulators of cardiovascular risk factors and are estimated to control more than 30 candidate miRNAs among night shift workers.Materials and Methods RNA was extracted from plasma samples of 110 night and 90day shift workers from Spain and Sweden who were part of the EPHOR study, followed by deoxyribonuclease treatment, complementary DNA synthesis, and quantitative real-time polymerase chain reaction using target-specific assays for five miRNAs (miR-122-5p, miR-107, miR-155-5p, miR-21-5p, and mir 103a-2-5p). We described characteristics of the study population, and expression levels of the miRNA assays. In adjusted linear regression models, we examined associations between night shift status and the log transformed relative expression levels of all miRNAs.Results Participants were on average 44 years of age, predominantly female (94, and worked in the health sector. We found that mir-21-5p, mir-155-5p, mir-103a-2-5p and mir-107 were highly correlated with each other, and mir-122-5p was moderately correlated with the other miRNAs. Results suggest higher expression levels of the miRNAs in night shift workers, most notably for mir-21-5p (coefficient 0.38, 950.11, 0.87) and mir-107 (coefficient 0.36, 950.13, 0.84), however results were not statistically significant.Conclusions Night shift work appeared to be associated with an elevated expression level of circulating miRNAs. Future work should explore potential dose-response associations between intensity and duration of night shift work and miRNA expression levels and also how these biomarkers relate to biomarkers of cardiovascular health among the population to further gain insight on the potential role of miRNA in cardiovascular health among night shift workers.Funding This work was funded by the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement number 874703. B.H. has received funding from the Instituto de Salud Carlos III (ISCIII) and the European Union NextGenerationEU/PRTR (Grant IHMC22/00017).