Leukocyte telomere length and coronary artery calcium

Patients with histories of myocardial infarction display shortened leukocyte telomere length (LTL), but conflicting findings have been reported on the relation between LTL and subclinical coronary artery atherosclerosis, as expressed by coronary artery calcium (CAC). The aim of this study was to examine the relation between LTL, measured by Southern blots, and CAC in 3,169 participants in the National Heart, Lung, and Blood Institute Family Heart Study. Participants consisted of 2,556 whites, 613 blacks, 1,790 women, and 1,379 men. The odds of having CAC ≥100 for the shortest LTL tertile versus the longest LTL tertile were 1.95 (95% confidence interval [CI] 1.28 to 3.16) in white men and 1.76 (95% CI 1.18 to 2.45) in white women, after adjusting for multiple covariates of CAC. The corresponding odds ratios for blacks were 1.53 (95% CI 0.67 to 3.50) and 0.87 (95% CI 0.37 to 2.00). Significance levels of tests for trend across LTL tertiles were p = 0.002 in white men, p = 0.006 in white women, p = 0.32 in black men, and p = 0.74 in black women. The associations, or lack of associations, were independent of C-reactive protein levels and other risk factors for CAC. As previously shown in other studies, whites displayed shorter LTLs than blacks (p <0.0001). In conclusion, the higher the coronary artery atherosclerotic burden in whites, the shorter the LTL. This LTL-atherosclerosis connection is not found in blacks. The mechanisms for the racial difference in LTL, CAC, and their interrelations do not seem to be related to inflammation and merit further research.