Rationale:
Leukocyte telomere length (LTL) is an indicator of biological aging. Telomere shortening may be sensitive to social stressors such as discrimination, but this has not been previously examined in a biracial cohort of patients with coronary heart disease (CHD).
Objective:
To explore differences in LTL by race and gender and examine whether discrimination was associated with accelerated cellular aging (shorter telomere length).
Methods:
Data were from 367 White and African American patients in the Mental Stress Ischemia Mechanisms and Prognosis Study (MIPS) which enrolled patients with a diagnosis of stable CHD from Emory University-affiliated hospitals and clinics. LTL was measured by quantitative polymerase chain reaction (qPCR) and expressed as a ratio of the amount of telomeric DNA to the amount of single-copy control gene (T/S). The T/S ratios were then converted to kilobase pairs. Discrimination was measured using the 10-item Everyday Discrimination Scale (EDS), where participants reported their experiences of everyday mistreatment during the previous 12 months. Responses were rated using 4-point Likert scales ranging from never = 1 to often = 4 which were summed. Due to the potential batch effect in telomere length, we modeled telomere plate as a random effect. Multiple linear regression models were stratified by race/ethnicity and gender to estimate differences in mean LTL and associations with discrimination, adjusted for potential confounding factors.
Results:
African American women had longer mean LTL (5.58; SD: 0.05) compared to African American men (5.28; SD: 0.04), White women (5.22; SD: 0.05) and White men (5.24; SD: 0.03). Reports of discrimination were higher among African American men (16.1; SD: 6.5) compared to African American women (15.4; SD: 4.9), White women (14.9; SD: 4.4), and White men (13.5; SD: 3.8). The association between discrimination and accelerated cellular aging was statistically significant among African American women [β = -0.02; 95% CI: (-0.04, -0.001); p=0.0377] after models were adjusted for demographics, smoking history, BMI, and disease history. Discrimination was not significantly associated with accelerated cellular aging among African American men [β = -0.01; 95% CI: (-0.02, 0.01)], White men β = [-0.003; 95% CI: (-0.02, 0.01)], or White women [β = -0.01; 95% CI: (-0.03, 0.01)]. The association between discrimination and accelerated cellular aging remained statistically significant for African American women after further adjusting for depression and perceived stress.
Conclusions:
Although African American women with CHD have longer telomere length, they may experience greater telomere shortening in relation to discrimination. Accelerated telomere shortening secondary to discrimination stress may be a potential mechanism of health related disparities among African American women with CHD.
Discrimination, Racial Bias, and Telomere Length in African-American Men