TOPLINE:

Weaker and fragmented circadian rest-activity rhythms (RARs) and later peak activity timing were associated with an increased risk for dementia in older adults, a new study showed.

METHODOLOGY:

• Researchers conducted a retrospective exam of 2016-2017 data from the ARIC study, assessing more than 2000 US participants (mean age, 79 years; 58% women).
• Participants wore the Zio XT Patch, a long-term continuous ambulatory ECG monitoring device, for more than 3 days (mean wear time, 12 days).
• RARs were derived from investigational accelerometer data. Assessments were made of relative amplitude and mesor (both measuring rhythm strength), intradaily variability (rhythm fragmentation), interdaily stability, and acrophase (time of peak activity).
• Dementia was ascertained using in-person assessments, telephone interviews using the cognitive status-modified or six-item screener, or hospitalization or death certificate codes.

TAKEAWAY:

• Over a median follow-up of 3 years, 176 participants (8%) developed dementia; 38% were diagnosed through in-person assessments, 35% through cognitive tests, and 27% through hospitalization or death certificate codes.
• Each 1-SD decrement in relative amplitude was associated with a 54% greater risk for dementia (adjusted hazard ratio [HR], 1.54; 95% CI, 1.32-1.78); and each 1-SD increment in intradaily variability was associated with a 19% greater risk (HR, 1.19; 95% CI, 1.02-1.38).
• Participants in the lowest tertile of amplitude and mesor had a higher dementia risk (HRs, 1.56 and 1.74, respectively) compared with those in the highest tertile.
• A later acrophase (time of peak activity) was linked to a greater risk for dementia (HR, 1.45) than normal acrophase.

IN PRACTICE:

Authors of an accompanying editorial noted that although “causality remains to be elucidated, this study suggests that RAR measures — particularly those reflecting rhythm strength, fragmentation, and timing — may serve as important prodromal markers of dementia and hold promise for early detection in older adults.”

They added that as wearable technology use continues to grow, “these findings highlight the potential of multidimensional RAR metrics as tools for personalized risk prediction and as targets for intervention.”

SOURCE:

This study was led by Wendy Wang, PhD, UT Southwestern Medical Center in Dallas. The editorial was led by Yi Fang, MD, University of California, San Francisco. Both articles were published online on December 29 in Neurology.

LIMITATIONS:

The study population consisted of older adults, which limited the generalizability of the findings to middle‑aged or younger populations. Dementia subtypes could not be distinguished because data on dementia etiology were not available. Additionally, the actigraphic-based results might not be directly comparable with previous studies.

DISCLOSURES:

The current research was funded by the National Heart, Lung, and Blood Institute; the National Institute of Neurological Disorders and Stroke; and the National Institute on Aging. One investigator reported a number of various disclosures, which are fully listed in the original article. The other investigators and the editorialists reported no relevant financial relationships.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.