The association between leukocyte telomere lengths and sleep instability based on cardiopulmonary coupling analysis

Purpose: The purpose of the study is to examine the objective association between sleep stability and leukocyte telomere lengths (LTL) using cardiopulmonary coupling (CPC) analysis, which is an electrocardiogram (ECG)-based technique to quantify physiologic sleep stability. Methods: Three hundred eighty-one healthy subjects were recruited from a community-based cohort study from the Korean Genome and Epidemiology Study (KoGES), and the associations between LTL and total quantities of different frequency coupling bands were examined using generalized linear model (GLM) with adjustment of significant covariates. Results: LTL showed a significant association with elevated narrow-band low frequency coupling (e-LFCNB, a CPC marker of periodic breathing or sleep fragmentation due to pathological respiratory chemoreflex activation) by interacting with obstructive sleep apnea (OSA) severity (p value of <0.0001). Especially, sleep stability significantly reduced with shortened LTL in OSA patients (Apnea-Hypopnea Index (AHI) ≥15) based on increased e-LFCNB which had a negative correlation with high-frequency coupling band (HFC), a marker of stable sleep. Conclusion: The present study suggested that shorter LTL might contribute to reduced sleep stability by interacting with OSA severity due to the stress of chronic sleep fragmentation or invariant sympathetic activity by respiratory chemoreflex activation.