The role of health behaviors in links between stress and epigenetic aging

High levels of stress are associated with accelerated epigenetic aging and health risks. However, less is known about the independent effects of different types of stress and whether these effects are explained by unhealthy behaviors. This study involved 1308 adults from the Midlife in the United States (MIDUS) study (53% female; 69% White, 22% Black; mean age: 54 years) to examine the independent effects of stressful life events and perceived stress on three DNA methylation-based measures of epigenetic aging (DNAm measures: GrimAge, DunedinPACE, PhenoAge). We also tested whether tobacco use, alcohol use, sleep problems, low diet quality, and low physical exercise mediate these effects. The results indicated that both perceived stress and stressful life events independently predict accelerated epigenetic aging indirectly through unhealthy behaviors across multiple DNAm measures of aging. Specifically, perceived stress predicted accelerated epigenetic aging through more sleep problems, lower diet quality, and lower physical exercise, whereas stressful life events predicted accelerated epigenetic aging through more tobacco and alcohol use as well as sleep problems. In addition, stressful life events directly predicted accelerated GrimAge above and beyond health behaviors. In summary, these findings underscore the critical role of health behaviors in linking different types of stress with biological aging and associated health issues.