The Effects of Sleep-Disordered Breathing on Arterial Stiffness are Modulated by Age

Study Objectives: To identify associations between sleep-disordered breathing (SDB) and arterial stiffness. Setting: Nested cross-sectional study. Participants: One hundred fifty-three participants (ages 45-77 years, 43% women) in the population-based Wisconsin Sleep Cohort. Eighty-three had SDB and were not using continuous positive airway pressure therapy. Interventions: Measurement of aortic pulse wave velocity (PWV) by arterial tonometry. Nocturnal polysomnography. Measurements and Results: SOB was defined as an apnea-hypopnea index (AHI) >= 5 events/hour of sleep. By study design those with SOB had higher mean (SD) AHI (17.6 [16.2] vs 2.2 [1.3] events/h), as well as lower average nocturnal O-2 saturation (91.5 [2.1] vs 93.0 [1.4] %, P < 0.001) and larger waist circumference (102.5 [13.2] vs 92.5 [12.5] cm, P < 0.001), but they had similar central aortic systolic (122.8 [15.1] vs 119.1 [11.8] mm Hg, P = 0.100) and diastolic blood pressures (77.1 [9.4] vs 77.4 [8.6] mm Hg, P = 0.834), and PWV (9.06 [2.15] vs 8.51 [1.88] m/s; all P > 0.10). Markers of SDB that were correlated with PWV were nocturnal O-2 saturation (r = -0.24, P = 0.004) and AHI (r = 0.18, P = 0.032); however, these associations were not statistically significant after adjustment. In subjects not on antihypertensive medications, a significant interaction between nocturnal O-2 saturation and age was identified (beta = -0.019, P = 0.039), such that the effect of nocturnal oxygen O-2 on PWV increased with age (adjusted R-2 = 0.468). Conclusions: Adverse effects of nocturnal oxygen desaturation on PWV are seen among normotensive individuals and are amplified with aging. Integrated assessment of SOB is necessary to characterize its effects on arterial stiffness.