Is there an association between altered baroreceptor sensitivity and obstructive sleep apnoea in the healthy elderly?

Obstructive sleep apnoea (OSA) is associated with a rise in cardiovascular risk in which increased sympathetic activity and depressed baroreceptor reflex sensitivity (BRS) have been proposed. We examined this association in a sample of healthy elderly subjects with unrecognised OSA. 801 healthy elderly (aged ≥65 years) subjects undergoing clinical, respiratory polygraphy and vascular assessment were examined. According to the apnoea-hypopnoea index (AHI), the subjects were stratified into no OSA, mild-moderate OSA and severe OSA cases. OSA was present in 62% of the sample, 62% being mild-moderate and 38% severe. No differences were found for BRS value according to sex and OSA severity. 54% of the group had normal BRS value, 36% mild impairment and 10% severe dysfunction. BRS was negatively associated with body mass index (p=0.006), 24-h systolic (p=0.001) and diastolic pressure (p=0.001), and oxygen desaturation index (ODI) (p=0.03). Regression analyses revealed that subjects with lower BRS were those with hypertension (OR 0.41, 95% CI 0.24-0.81; p=0.002) and overweight (OR 0.42, 95% CI 0.25-0.81; p=0.008), without the effect of AHI and ODI. In the healthy elderly, the presence of a severe BRS dysfunction affects a small amount of severe cases without effect on snorers and mild OSA. Hypertension and obesity seem to play a great role in BRS impairment.