Sedentary Behavior Tied to Cognitive Decline in Older Adults

Medscape

28-05-2025

In older adults, increased sedentary time was associated with smaller brain volume, greater neurodegeneration, and worse cognitive performance, especially among apolipoprotein E ( APOE ) ε4 carriers, new research suggested. These associations persisted over a 7-year period, even among people who achieved recommended levels of moderate to vigorous physical activity (MVPA).
METHODOLOGY:
This study included 404 adults aged 60 years or older (mean age, 71 years; 54% men; 85% White, non-Hispanic) from the Vanderbilt Memory and Aging Project who were cognitively unimpaired or met criteria for early mild cognitive impairment at baseline.
Researchers collected actigraphy data using wrist-worn accelerometers for 24 hours on 7 consecutive days and performed neuropsychological assessments and 3T brain MRI over a 7-year period.
The analysis included both cross-sectional and longitudinal evaluations of sedentary time in relation to brain structure and cognition, and covariates included age, sex, race/ethnicity, APOE-ε4 carrier status, and MVPA.
TAKEAWAY:
The average sedentary time among participants was 13 h/d, and 87% of participants engaged in Centers for Disease Control and Prevention recommended levels of MVPA (average, 61 min/d).
In the cross-sectional unadjusted analysis, increased sedentary time was associated with a smaller Alzheimer's disease neuroimaging signature ( P = .01) and worse episodic memory performance ( P = .003) but was no longer significant after adjusting for MVPA.
= .01) and worse episodic memory performance ( = .003) but was no longer significant after adjusting for MVPA. In the cross-sectional analysis adjusted for MVPA, among APOE-ε4 carriers, increased sedentary time was associated with smaller volumes of frontal ( P = .02) and parietal ( P = .03) lobes, reduced total gray matter volume ( P = .02), and lower performance on the Boston Naming Test ( P = .01) and Hooper Visual Organization Test ( P = .01).
carriers, increased sedentary time was associated with smaller volumes of frontal ( = .02) and parietal ( = .03) lobes, reduced total gray matter ( = .02), and lower performance on the Boston Naming Test ( = .01) and Hooper Visual Organization Test ( = .01). In the longitudinal analysis, increased sedentary time was associated with a reduction in hippocampal volume ( P = .008). Among APOE-ε4 carriers, it was associated with a reduction in occipital volume ( P = .03).
IN PRACTICE:
'These findings are particularly important in the context of aging, as mobility limitations and greater sedentary time increases in older adults. From a personalized medicine approach, healthcare professionals might consider assessing not only a patient's exercise regimen but also the amount of time they are sedentary throughout the day, recommending a reduction in such sedentary behavior in addition to increasing daily physical activity,' the study authors wrote.
SOURCE:
This study was led by Marissa A. Gogniat, Vanderbilt Memory and Alzheimer's Center, Nashville, Tennessee. It was published online on May 13 in Alzheimer's and Dementia .
LIMITATIONS:
This study included a racially homogenous, highly educated, and physically active sample, which may have limited its generalizability. Methodological limitations included the use of cross-sectional rather than longitudinal MRI registration, the use of individual neuropsychological subtests instead of composites, and a potential inaccuracy due to wrist-worn actigraphy devices. This study also did not conduct a full 24-hour compositional activity analysis, which could have improved the assessment of optimal activity, sedentary behavior, and sleep distribution.
DISCLOSURES:
This study was funded by the Alzheimer's Association, National Institute on Aging, Vanderbilt Institute for Clinical and Translational Research, Vanderbilt University High-Performance Computer Cluster for Biomedical Research, and the Richard Eugene Hickman Alzheimer's Disease Research Endowment. One author reported serving on the scientific advisory board for Vivid Genomics and holding editorial roles with the Alzheimer's and Dementia and Alzheimer's and Dementia: Translational Research and Clinical Intervention .