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AlzRisk Paper Detail

Reference: Verghese, 2003
Cohort: Bronx Aging Study
Risk Factor: Blood Pressure

Average Follow-up Time Detail
Volunteers between the ages of 75 and 85 were recruited in 1980-1983. Participants scoring 8 or fewer errors on the Blessed Information-Memory-Concentration test were considered dementia-free and formed the initial cohort. Participants were followed until 2001 for a possible 21 years of follow-up, with a median 6.7 years of follow-up.

Exposure Detail
"Trained registered nurses measured BP at each visit. Four readings at 1-minute intervals were taken from the right forearm after 5 minutes of rest in a sitting position. The second and fourth readings were done with random zero mercury sphygmomanometer, and the mean of these two readings was used for analyses. Systolic Korotkoff phase I and the diastolic Korotkoff phase V were used as cutoff points. Mean arterial pressure was calculated as the sum of the diastolic BP and one-third pulse pressure (systolic - diastolic BP)."

Ethnicity Detail
Inclusion criteria included "English-speaking."

Age Detail
Participants were ages 75-85 at baseline.

Screening and Diagnosis Detail
Screening Method:
BlessedBlessed Information-Memory-Concentration Test

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

Total dementia definition: DSM-III/DSM-IIIR

"At study visits, subjects with suspected dementia, based on study clinicians’ evaluations, neuropsychological tests, or worsening Blessed test scores (by 4 points or a total score over 7), received a workup, including a CT scan and blood tests (complete blood count, routine chemical screen, liver and thyroid function tests, vitamin B12 and folate levels, and syphilis serology).17,18 A diagnosis of dementia was assigned at consensus case conferences attended by the study neurologists, neuropsychologist, and a geriatric nurse clinician, using the criteria of the Diagnostic and Statistical Manual for Mental Disorders (3rd ed. and 3rd rev. ed. after 1986).24,25

As updated criteria for dementia and subtypes were introduced after the study launch, all cases were reconferenced in 2001 to ensure uniformity of diagnosis by a neurologist and a neuropsychologist who did not participate in the original Bronx Aging Study conferences. Dementia diagnosis followed the criteria of the Diagnostic and Statistical Manual (3rd. rev. ed.).25 The raters were not blinded to clinical evaluations, though BP measurements were not used to define dementia.17–19 Disagreements between raters were resolved by consensus after presenting the case to a second neurologist. Dementia was subtyped using established criteria for probable/possible AD,26 probable/possible/mixed vascular dementia,27 and probable/possible dementia with Lewy bodies.28 We have previously reported good validity for clinical diagnosis using pathologic diagnosis as the gold standard.19,21,29,30"

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

"Subjects were censored when they were diagnosed with dementia, at death, or at final study contact."

AD Covariates:

TD Covariates: