0305 Degraded Fractal Activity Regulation and Incident Parkinsonism in Community-Based Older Adults. (12th April 2019)

• Record Type: Journal Article
• Authors: Hu, Kun; Yu, Lei; Lim, Andrew S P; Buchman, Aron S; Schneider, Julie A; Bennett, David A; Li, Peng
• Is Part Of: Sleep. Volume 42(2019)Supplement 1
• Page Start: A124
• Page End: A126
• Publication Date: 2019-04-12
• Subjects: Sleep -- Physiological aspects -- Periodicals; Sleep disorders -- Periodicals; Sommeil -- Aspect physiologique -- Périodiques; Sommeil, Troubles du -- Périodiques; Sleep disorders; Sleep -- Physiological aspects; Sleep -- physiological aspects; Sleep Wake Disorders; Psychophysiology; Electronic journals; Periodicals; 616.8498
• DOI: 10.1093/sleep/zsz067.304
• Languages: English
• ISSNs: 0161-8105

Abstract

Abstract: Introduction: Healthy physiological systems exhibit fractal regulation, generating similar fluctuation patterns in physiological outputs across different time scales from seconds to hours. Evidence indicates a mechanistic link between fractal regulation and sleep/circadian control, and both degraded with aging and in diseases. It is accepted that sleep and circadian disturbances are common non-motor symptoms of Parkinson's disease (PD). We tested whether degraded fractal regulation is associated with incident Parkinsonism. Methods: We examined 810 older adults (620 females; age: 80.4±7.2 [SD], range 59.4-98.9) in the Rush Memory and Aging Project who were free from any parkinsonian signs at baseline and had undergone annual motor tests for assessment of 4 parkinsonian signs (i.e., bradykinesia, gait, rigidity, and tremor) for up to 13 years. Parkinsonism was rendered if ≥2 parkinsonian signs presented. Motor activity was monitored on the wrist continuously for up to 10 days at baseline. Detrended fluctuation analysis was performed to obtain a metric α that quantifies fractal temporal correlations of motor activity at time scales ~0.1-1.5h. A Cox proportional hazards model was performed to examine the association of α with incident Parkinsonism. Results: Parkinsonism was observed in 332 subjects (~41%) after 3.9±2.8 [SD] years on average from baseline. Older age (hazard ratio [HR]=1.07, p<0.0001) and less education (HR=1.07, p=0.002) but not sex (p=0.6) were associated with a higher risk of Parkinsonism. After controlled for age, sex, and education, 1-SD decrease in α (0.06) was also associated with increased risk for Parkinsonism with an HR of 1.22 (95% CI: 1.09-1.37, p=0.001). The effect is equivalent to that of being ~2.9 years older. The association remained after further adjusting for actigraphy-derived sleep and/or circadian metrics (i.e., sleep fragmentation and interdaily stability). Conclusion: Degraded fractal regulation was associated with increased PD risk. Even though previous studies have well documented the mechanistic link between fractal regulation and sleep/circadian control, the effect of fractal degradation on PD risk appears to be independent from sleep/circadian control. Support (If Any): This work was supported by NIH grants R01AG048108, RF1AG059867, R01AG017917, and R01NS078009.