Telomeres are regions at the ends of chromosomes that maintain chromosomal structural integrity and genomic stability. In studies of mainly older, white populations, shorter leukocyte telomere length (LTL) is associated with cardiometabolic risk factors and increased risks of mortality and coronary heart disease (CHD). On average, African Americans (AfAm) have longer LTL than whites, but the LTL-CHD relationship in AfAm is unknown. We investigated the relationship of LTL with CHD and mortality among AfAm.
Using a case-cohort design, 1525 postmenopausal women (667 AfAm and 858 whites) from the Women's Health Initiative had LTL measured in baseline blood samples by Southern blotting. CHD or mortality hazards ratios were estimated using race-stratified and risk factor-adjusted Cox proportional hazards models. There were 367 incident CHD (226 mortality) events in whites, whereas AfAm experienced 269 incident CHD (216 mortality) events during median follow-up of 13 years. Shorter LTL was associated with older age, current smoking, and white race/ethnicity. In whites, each 1 kilobase decrease in LTL was associated with 50% increased hazard of CHD, hazard ratio=1.50 (95% confidence interval, 1.08-2.10), P=0.017. There was no association between CHD and LTL in AfAm. White women with shorter LTL had higher risks of mortality. In contrast, shorter LTL was weakly associated with decreased mortality hazard in AfAm.
As one of the largest prospective studies of LTL associations with incident CHD and mortality in a racially diverse sample, our study suggests differences in LTL associations with CHD and mortality between white and AfAm postmenopausal women.