Electrocardiogram QRS duration and associations with telomere length: A cross-sectional analysis in Australian rural diabetic and non-diabetic population.

Prolonged electrocardiogram QRS durations are often present in aging populations. Shorter telomere length is considered a biomarker of cellular aging. Decreased telomere length has been associated with coronary artery risk, and ventricular remodeling. However, the association between telomeres and cardiac conduction abnormalities, such as increased QRS duration are not well understood. A retrospective cross-sectional population was obtained from the CSU Diabetes Screening Research Initiative database where 273 participants had both ECG-derived QRS duration and DNA to permit leukocyte telomere length (LTL) determination. Telomere length was determined using the monochrome multiplex quantitative PCR method to measure mean relative LTL. Resting 12-lead electrocardiograms were obtained from each subject using a Welch Allyn PC-Based ECG system. Relative LTL was moderately negatively associated with QRS duration in type 2 diabetes mellitus (T2DM) patients (R=0.055), compared to controls (R=0.010). In general linear models with no adjustments a significant interaction between QRS duration and LTL is observed for a combined population of T2DM and non-diabetics. When we compared T2DM to non-diabetics, we found that T2DM increased the effect size for relative LTL on QRS duration in comparison to controls. Hence, for each 0.1 unit of relative LTL attrition, QRS duration in T2DM patients increased by 3.24ms (95% CI, -63.00 to -1.84), compared to 1.65ms in controls (95% CI, -40.44 to 7.40). In summary we have observed an association between LTL in a rural aging mixed population of T2DM and non-diabetes. We have observed an unadjusted association between QRS duration and LTL in T2DM. We noted that the control group demonstrated no such association. This highlights the complexity of T2DM when exploring disease phenotype-telomere interactions.