Telomere length and cardiovascular protection during chronic air pollution
M Sagris, S T Toupance, P T Theofilis, E O Oikonomou, N B Barbaresos, M N A Asimakopoulos, B C Clerc, C L Lakomy, G L Lazaros, K T Tsioufis, A B Benetos, D T TousoulisAbstract
Objective
Higher air pollution exposure and shorter leukocyte telomere length (LTL) are both associated with increased risk of cardiovascular disease. In this study we examined whether air pollution exposure is associated with shorter LTL and whether LTL can modulate the effects of pollution exposure on cardiovascular state.
Design and Method
In this cross-sectional analysis we selected 418 individuals, aged 62.4 ± 11.8 years, from the "Corinthia" study which was conducted in the homonym region in Greece. Half of the participants lived in a high air pollution area (HAPA) according to the CO, NO2 and SO2levels and the other half in a low air pollution area (LAPA). LTL was measured from whole blood by Southern blot and carotid-femoral pulse wave velocity (cfPWV), carotid intima media thickness (cIMT) and presence of carotid plaque were determined to evaluate atherosclerotic burden.
Results
We found no difference in age and sex adjusted LTL between HAPA and LAPA groups (p=0.42). In multivariate analysis including age, sex, as co-factors, participants of HAPA whose exposure began at an earlier age (≤ 20 years) had significantly shorter LTL compared to those exposed at >20 years of age (B=-0.169, p=0.012). Using the median LTL (6.78 kb) as a cutoff, the cohort was divided into four groups: Group 1 - LAPA/Long LTL (108 subjects), Group 2 - LAPA/Short LTL (98 subjects), Group 3 - HAPA/ Long LTL (102 subjects), and Group 4 - HAPA/Short LTL (110 subjects). Group 4 patients had significantly greater cf-PWV and cIMT compared to the other three groups (p<0.05), whereas there was no intragroup difference between the other clusters. These differences subsisted after adjustment for age and sex. Carotid plaque prevalence increased from 17.9% for Group 1 to 22.5% for Group 2, 29.7% for Group 3 and 40.4% for Group 4 (p < 0.01).
Conclusion
Prolonged exposure to high air pollution starting early in life seems to display a negative effect on telomere dynamics. Presence of longer telomeres may at least partially protect from negative effects of high air pollution exposure on vascular health. These results could be used for personalized cardiovascular risk prevention.Summary Figure