Abstract 12275: Sleep Duration: Associations for Cognitive Function and Visit-to-visit Blood Pressure Variability
Background Recent studies have shown that short or long sleep duration was associated with cardiovascular disease and cognitive impairment. On the other hand, increased visit-to-visit variability in systolic blood pressure (SBP) and impaired kidney function were shown to be predictors of cardiovascular disease. In this study, the associations of sleep duration with cognitive function and visit-to-visit BP variability were investigated.
Method Subjects consisted of 201 elderly individuals (79.9±6.4 years old; hypnotic use, 35%) with one or more cardiovascular risks (hypertension, diabetes, hyperlipidemia, and smoking). We performed carotid artery ultrasound and assessed cognitive function using the Mini Mental State Examination (MMSE). Kidney function was estimated based on serum cystatin C (eGFRcys). Based on 12 visits (once a month), visit-to-visit SBP variability (expressed as a coefficient of variation [CV]) and delta (maximum-minimum) BP were measured.
Result According to the quartile of habitual sleep duration, subjects were classified into 4 groups (<6, 6-7.5, 7.5-9, 9< hours per day). Significant associations were observed between the four quartiles of sleep duration and each of MMSE score (p<0.001), eGFRcys (p<0.001), delta SBP (p<0.001), and CV SBP (p<0.05). In the multiple linear regression analysis adjustment for covariates including eGFRcys, mean carotid artery intima-media thickness, long sleep duration (B: 7.53; 95%CI: 0.73 to 14.3; p<0.05) was significantly associated with delta SBP when subjects with sleep duration of 6-9 hours were used as a reference group. And short (B: -1.78; 95%CI: -3.16 to -0.40; p<0.05) and long sleep durations (B: -5.86; 95%CI: -7.22 to -4.49; p<0.001) were significantly associated with MMSE score after adjustment for covariates including the brain natriuretic peptide level, eGFR-cys, CV SBP, and delta SBP.
Conclusion In the high risk elderly, short or long sleep duration was associated with lower cognitive function and higher visit-to-visit BP variations. Specifically, the relationship between long sleep duration and cognitive function might be independently of visit-to-visit BP variability. Physicians should inquire about sleep duration in the elderly at high risk of cardiovascular disease.
- © 2012 by American Heart Association, Inc.