Article

Mild cognitive impairment (MCI) represents a transition between
normal cognitive aging and dementia and may represent a critical time frame for
promoting cognitive health through behavioral strategies. Current evidence
suggests that physical activity (PA) and sedentary behavior are important for
cognition. However, it is unclear whether there are differences in PA and
sedentary behavior between people with probable MCI and people without MCI or
whether the relationships of PA and sedentary behavior with cognitive function
differ by MCI status. Objective: The aims of this study were to examine
differences in PA and sedentary behavior between people with probable MCI and
people without MCI and whether associations of PA and sedentary behavior with
cognitive function differed by MCI status. Design: This was a cross-sectional
study. Methods: Physical activity and sedentary behavior in adults dwelling in
the community (N = 151; at least 55 years old) were measured using a wrist-worn
actigraphy unit. The Montreal Cognitive Assessment was used to categorize
participants with probable MCI (scores of <26/30) and participants without MCI
(scores of >/=26/30). Cognitive function was indexed using the Alzheimer Disease
Assessment Scale-Cognitive-Plus (ADAS-Cog Plus). Physical activity and sedentary
behavior were compared based on probable MCI status, and relationships of
ADAS-Cog Plus with PA and sedentary behavior were examined by probable MCI
status. Results: Participants with probable MCI (n = 82) had lower PA and higher
sedentary behavior than participants without MCI (n = 69). Higher PA and lower
sedentary behavior were associated with better ADAS-Cog Plus performance in
participants without MCI (beta = -.022 and beta = .012, respectively) but not in
participants with probable MCI (beta < .001 for both). Limitations: This study
was cross-sectional and therefore could not establish whether conversion to MCI
attenuated the relationships of PA and sedentary behavior with cognitive
function. The diagnosis of MCI was not confirmed with a physician; therefore,
this study could not conclude how many of the participants categorized as having
probable MCI would actually have been diagnosed with MCI by a physician.
Conclusions: Participants with probable MCI were less active and more sedentary.
The relationships of these behaviors with cognitive function differed by MCI
status; associations were found only in participants without MCI.

Langue : ANGLAIS