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AlzRisk Paper Detail
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Reference: de Bruijn, 2013
Cohort: Rotterdam Study
Risk Factor: Physical Activity


Average Follow-up Time Detail
Baseline evaluation occurred from 1997 through 1999.

Exposure Detail
Physical activity was measured using an adapted version of the Zutphen Physical Activity Questionnaire, which contains questions on walking, cycling, gardening, recreational physical activity, and housekeeping. Participants were asked how many hours were spent on each activity per week in the previous two weeks, and for recreational or gardening activities, if these activities were only practiced in the summer or winter. Metabolic equivalent of task (MET) hours per week was calculated based on responses to the questionnaire. Because of a skewed distribution, the median is displayed instead of the mean. In regression analysis, MET-hours per week was first log transformed and analyed per standard deviation increase.

Ethnicity Detail
Investigators do not provide data on ethnicity. All participants were residents of a suburb of Rotterdam, Netherlands.

Screening and Diagnosis Detail
Screening Method:
CAMDEXCambridge Examination for Mental Disorders of the Elderly
GMSGeriatric Mental State Schedule (Copeland 1976)
MMSEMini-Mental State Examination (Folstein 1975)

AD Diagnosis:
DSM IIIR Diagnostic and Statistical Manual III-Revised
NINCDS ADRDA National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association Criteria (McKhann 1984)

Total dementia definition: Dementia via DSM-III-R.

"Participants were screened for dementia at baseline and follow-up examinations using a three-step protocol. Screening was done using the Mini-Mental State Examination (MMSE) and the Geriatric Mental Schedule (GMS) organic level [30, 31]. Screen-positives (MMSE <26 or GMS organic level >0) subsequently underwent an examination and informant interview with the Cambridge Examination for Mental Disorders in the Elderly(CAMDEX) [32]. Participants who were suspected of having dementia, underwent, if necessary, further neuropsychological testing. Additionally, the total cohort was continuously monitored for dementia through computerized linkage between the study database and digitized medical records from general
practitioners and the Regional Institute for Outpatient Mental Health Care. When information on neuro-imaging was required and available, it was used for decision making on the diagnosis. In the end, a consensus panel, led by a neurologist, decided on the final diagnosis in accordance with standard criteria using the DSM-III-R criteria for dementia and the NINCDS-ADRDA for Alzheimer disease."

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

Follow-up time was used as the time scale in Cox proportional hazards models.

AD Covariates:
Aage
Eeducation
Ggender
APOE4APOE e4 genotype
MMSEbaseline MMSE
BMIbody mass index
DMdiabetes mellitus
HDLHDL cholesterol
HTNhypertension
SMsmoking status
TCtotal cholesterol

TD Covariates:
Aage
Eeducation
Ggender
APOE4APOE e4 genotype
MMSEbaseline MMSE
BMIbody mass index
DMdiabetes mellitus
HDLHDL cholesterol
HTNhypertension
SMsmoking status
TCtotal cholesterol