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AlzRisk Paper Detail

Reference: Wilson, 2007
Cohort: Memory and Aging Project
Risk Factor: Cognitive Activity

Average Follow-up Time Detail
The total person-time of follow-up was 1932.6 person-years. The average follow-up time was 2.5 years and the maximum follow-up time was 5 years.

Exposure Detail
Study participants were asked at baseline about the frequency with which they participated in nine cognitive leisure activities, such as reading the newspaper and watching television. For each activity, the investigators scored participation as follows: "every day or about every day" (5 points), "several times a week" (4 points), "several times a month" (3 points), "several times a year" (2 points) and, "once a year or less" (1 point). On this scoring scale, 1 point corresponds to a one-step increment in participation frequency. A composite cognitive activity scale score ranging from 1 to 5 was obtained by averaging participation scores across the assessed cognitive activities. In this study, the mean composite cognitive activity score was 3.2 (SD = 0.7).

"Past and current frequency of participation in cognitively stimulating activities was assessed with a structured questionnaire at baseline.18 There were 30 items on past activity including 11 about childhood (3 items for age 6 and 8 items for age 12), 10 items about young adulthood (age 18), and 9 items about middle age (age 40). There were 9 items about current activity which were readministered annually...Items included activities like reading a newspaper, playing games like chess or checkers, visiting a library, or attending a play. Frequency of participation was rated from 1 (once a year or less) to 5 (every day or about every day). Composite measures of current (9 items) and past (30 items) cognitive activity were formed by averaging the item scores in each period."

Ethnicity Detail
In this analytic sample, 91% of the participants are Caucasian.

Screening and Diagnosis Detail
Screening Method:
CERADConsortium to Establish a Registry for Alzheimer's Disease (Morris 1989)

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

"Participants underwent a uniform clinical evaluation at baseline which was repeated annually thereafter with examiners blinded to all previously collected data. The evaluation included a structured medical history, complete neurologic examination, and detailed testing of cognitive function. On the basis of this evaluation, an experienced clinician classified persons with respect to dementia and AD following the guidelines of the joint working group of the National Institute of Neurological and Communicative Disorders and Stroke and the AD and Related Disorders Association.13"

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

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