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

SDB was defined as an apnea-hypopnea index (AHI) > or = 5 events/hour of sleep. By study design those with SDB had higher mean (SD) AHI (17.6 [16.2] vs 2.2 [1.3] events/h), as well as lower average nocturnal O2 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 O2 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 O2 saturation and age was identified (beta = -0.019, P = 0.039), such that the effect of nocturnal oxygen O2 on PWV increased with age (adjusted R2 = 0.468).

CONCLUSIONS

Adverse effects of nocturnal oxygen desaturation on PWV are seen among normotensive individuals and are amplified with aging. Integrated assessment of SDB is necessary to characterize its effects on arterial stiffness.