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AlzRisk Paper Detail

Reference: Buchman, 2012
Cohort: Memory and Aging Project
Risk Factor: Physical Activity

Average Follow-up Time Detail
Participants were followed-up for a mean of 3.5 years (SD=1.54).

Exposure Detail
Total daily exercise and nonexercise physical activity was measured 24 hours/day for up to 10 days with actigraphs worn on the nondominant wrist. Physical activity was measured with actigraphy
(Actical®; Mini Mitter, Bend, OR). Total daily physical activity was the average sum of all daily activity counts recorded[13]. On average, there were more than 3 x 10^5 activity counts/day; raw counts were divided by 1 x 10^5 (about 1 SD) to facilitate presentation and interpretation of the results.

Ethnicity Detail
Not reported. The population comprises residents of Chicago, Illinois, USA.

Screening and Diagnosis Detail
AD Diagnosis:
NINCDS ADRDA National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association Criteria (McKhann 1984)

"Cognitive function was assessed using a battery of 19 tests which were used to create a composite measure of global cognition as described elsewhere[12]. Cognitive testing was scored by computer and reviewed by a neuropsychologist to diagnose cognitive impairment. Participants were then evaluated by a clinician who used all cognitive and clinical data to diagnose AD using National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer’s Disease and Related Disorders Association criteria."

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

"Next, we examined the association of total daily physical activity with incident AD using a discrete-time Cox proportional hazards model with terms that adjusted for age, sex, and education[18]. Next we added terms to this core model to examine potential confounders and modifiers."

AD Covariates:
CA-PastPast Cognitive Activity
PAphysical activity
SAsocial Activity