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AlzRisk Paper Detail

Reference: Luchsinger, 2005
Cohort: Washington Heights-Inwood Columbia Aging Project
Risk Factor: Blood Pressure

Average Follow-up Time Detail
"Baseline data were collected from 1992 through 1994. Follow-up data were collected at intervals of approximately 18 months. This study includes data collected up to 2003."

Mean follow up time was 5.5 years (SD: 3.2)

Exposure Detail
Hypertension was "defined by self-report at baseline and at each follow-up interval or by the use of disease specific medications. Blood pressure measurements were also considered in the definition of hypertension. Hypertension was defined as a systolic blood pressure over 140 mm Hg or a diastolic blood pressure over 90 mm Hg.29 Blood pressure levels did not increase the predictive value of the self-report of hypertension, and we report results only for the definition by self-report."

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)

"The diagnosis of dementia was established based on all available information gathered from the initial and follow-up assessments. Dementia was determined by consensus at a conference of physicians, neurologists, neuropsychologists, and psychiatrists. The diagnosis of dementia was based on standard research criteria40 and required evidence of cognitive decline, including memory impairment, on the neuropsychological test battery as well as evidence of impairment in social or occupational function (Clinical Dementia Rating score of 0.5).41 The diagnosis of AD was based on the National Institute of Neurological and Communication Disorders and Stroke/Alzheimer’s Disease and Related Disorders Association criteria.42 A diagnosis of probable AD was made when the dementia could not be explained by any other disorder. A diagnosis of possible AD was made when the most likely cause of dementia was AD, but there were other disorders that could contribute to the dementia, such as stroke and Parkinson disease(PD)."

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

"Each risk factor was treated as a time-dependent covariate specified by the follow-up date when the diagnosis was made.... Cox proportional hazards regression models43 were used to estimate the association between vascular risk factors and the risk of incident AD. We present two models for the multivariate analyses: one adjusted including sex as a covariate and the other including years of education, the APOE-ε4 allele, and stratified by ethnic group and education category. We also conducted secondary analyses adjusting for the presence of stroke. The time-to-event variable was the age at onset of dementia.44 …. If individuals had dementias other than the one used as the outcome in the analyses, they were censored at the time of dementia diagnosis."

AD Covariates:
APOE4APOE e4 genotype