[The relationship between the relative length of leukocyte telomeres and mtDNA copy number and acute coronary syndrome in a 15-year follow-up.]

OBJECTIVE: to study the association of relative leukocyte DNA telomere length with death from natural causes during a 15-year follow-up in a middle-aged and elderly Siberian population. Study of the association of the relative length of leukocyte telomeres (LTL) with fatal outcomes during a 15-year follow-up of a random population sample formed in 2003-2005 (n=9 360, 45-69 years old, Novosibirsk, HAPIEE project). The main group included the persons died from natural causes (except external) without a previous history of CVD and cancer (n=609); controls were stratified by sex and age (n=799). The analysis of relative LTL at baseline was performed using quantitative real-time PCR. We estimated the odds ratio of all-cause death per 1 decile shortening of LTD as a continuous variable in a multivariable-adjusted logistic regression. The carriers of shorter telomere carriers had an increased risk of death from natural causes over the next 15 years (OR=1,37, 95% CI 1,31-1,44) per decile of LTL decrease, regardless of other factors. The risk coefficients were similar for death from CVD (1,39), cancer (1,42), and other non-external causes (1,51). In studied middle-aged and elderly Siberian (Caucasoid) population cohort the LTL was an independent inverse predictor of the 15-year risk of death from natural causes.

[The relationship between the relative length of leukocyte telomeres and mtDNA copy number and acute coronary syndrome in a 15-year follow-up.]

We studied the relationship between the leucocyte telomere length (LTL) and the copy number of mitochondrial DNA (CNmtDNA) and the development of acute coronary syndrome during 15 years of follow-up. A random population sample was examined at baseline in 2003-2005 (n=9 360, men and women 45-69 years old, Novosibirsk, the HAPIEE project) and followed-up for 15 years. In the frame of nested case-control design, we selected cases - incident myocardial infarction/acute coronary syndrome (MI/ACS) among those free from baseline CVD (n=256) and sex- and age-stratified control among those free from baseline CVD and cancer and alive by the end of follow-up (n=799). The relative LTL and CNmtDNA were assessed using quantitative real-time PCR. Results. The carriers of shorter telomeres had increased 15-year risk of MI/ACS with adjusted OR=1,87 (95% CI 1,70-2,06) per 1 LTL decile independent of other factors. Fewer CNmtDNA was associated with increased risk of MI/ACS with adjusted OR=1,19 (95% CI 1,12-1,26) per 1 CNmtDNA decile. The identified associations were confirmed in tertile analysis and in stepwise analysis with continuous variables of both biomarkers. All associations persisted after adjusting for gender, age, and traditional CVD risk factors. Conclusion. The LTL and CNmtDNA were independent predictors of the 15-year risk of MI/ACS in the middle- and elderly Siberian (Caucasoid) population cohort. These findings highlight the need for further research to elucidate the mechanisms by which LTL and mtDNA copy number may affect human health.