Introduction:
Leukocyte telomere length (LTL), a biomarker of cellular aging, is associated with human longevity. Psychosocial stressors are associated with shorter LTL. African Americans (AAs) experience greater stressor levels compared to other racial and ethnic groups. Research on associations of psychosocial factors with LTL among AAs is not well understood. Using Jackson Heart Study (JHS) data, we examined associations of psychosocial factors (negative affect and stressors) with LTL among AAs.
Hypothesis:
We hypothesized that psychosocial factors are inversely associated with LTL.
Methods:
Analysis was restricted to 2,516 JHS participants with LTL and psychosocial data between 2000-2004. Cross-sectional associations of negative affect [cynical distrust, anger-in, anger-out, depressive symptoms] and stressors [perceived stress, weekly stress inventory event (WSI-event), WSI-impact, major life event (MLE)] were examined with LTL among participants aged 21-95 years old (women=1,542; men=974). Psychosocial variables were measured by standardized questionnaires; LTL was measured by Southern blot. Summations of the four psychosocial measures were created for negative affect and stressors, with scores ranging from 4-12. We expressed each individual psychosocial measure into categories (tertiles: low, moderate, high) and in continuous standard deviation (SD) units. Using multivariable linear regression we evaluated the associations of psychosocial factors with mean differences (beta coefficient, b) in LTL adjusting for demographics (Model 1), socioeconomic status (SES) (Model 2), health behaviors, cardiovascular disease (CVD) risk factors (Model 3), and coping (Model 4).
Results:
High (vs low) anger-out was inversely associated with LTL in Model 1 (b = -0.043, p=0.008) and Model 2 (b = -0.0395, p=0.03), where 1-SD unit increase in anger-out was associated with shorter LTL. High (vs low) cumulative negative affect was marginally associated with insignificantly shorter LTL in Model 1 (b = -0.09, p=0.06) and Model 2 (b = -0.09, p=0.07) before transformation to SD units. There was no association between psychosocial stressors and shorter LTL in this sample. Paradoxically, high (vs low) WSI-event was positively associated with LTL (b =0.042, p=0.016), where 1-SD unit increase in WSI-event was associated with longer LTL after full adjustment.
Conclusion:
Depressive symptoms were associated with LTL shortening in the literature. The current study associates anger-out with shorter LTL, while WSI-event was associated with longer LTL among AAs in the JHS. Possibly, stress pathways that effect telomere length vary, where high stress can trigger LTL lengthening or shortening. Mechanisms of the paradoxical association between stress and telomere length must be further explored among AAs.
Response to Letter Regarding Article, “Association of Leukocyte Telomere Length With Circulating Biomarkers of the Renin-Angiotensin-Aldosterone System: The Framingham Heart Study”