BACKGROUND: Stress is a key precipitant for many common diseases, but established biological markers to track stress and guide investigations into mechanisms linking stress and disease are lacking. Cross-sectional studies have identified correlations between stress and telomere attrition, but no large, longitudinal studies examining the impacts of chronic stress on telomere length exist. Residency training for physicians is a well-established stressful experience and can be used as a prospective stress model.
METHODS: In a longitudinal cohort study of 250 interns (first-year residents) at 55 United States hospital systems serving during the 2015-2016 academic year, we examined associations between measures of the residency experience and saliva-measured telomere attrition.
RESULTS: Telomere length shortened significantly over the course of internship year, from mean ± SD of 6465.1 ± 876.8 base pairs before internship to 6321.5 ± 630.6 base pairs at the end of internship (t = 2.69; p = .008). Stressful early family environments and neuroticism were significantly associated with shorter preinternship telomere length. Longer work hours were associated with greater telomere intern telomere loss over the year (p = .002). Of note, the mean telomere attrition during internship year was six times greater than the typical annual attrition rate identified in a recent meta-analysis.
CONCLUSIONS: This work implicates telomere attrition as a biologically measurable consequence of physician training, with the magnitude of attrition associated with workload. Identification of an objective, biological sequela of residency stress may help to facilitate the development of effective interventions. Further, the findings implicate telomere attrition as an objective biomarker to follow the pathologic effects of stress, in general.