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AlzRisk Paper Detail
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Reference: Muller, 2007
Cohort: Washington Heights-Inwood Columbia Aging Project
Risk Factor: Obesity


Average Follow-up Time Detail
"Baseline data were collected from 1992 through 1994 (cohort 1) in 2126 subjects and from 1999 through 2002 (cohort 2) in 2183 subjects. The assessments, including neuropsychological battery, were repeated every 18 months."

Exposure Detail
Method of exposure ascertainment: technician measurement

"Waist circumference was measured at the level of the iliac crest at minimal inspiration to the closest 0.1 cm."

Participants with waist circumferences exceeding 102 cm for men and 88 cm for women were classified as having a high waist circumference.

Ethnicity Detail
"Ethnic group was classified by self-report using the format of the 1990 US Census. Individuals were separated into 3 ethnic groups: African-American (non-Hispanic), Hispanic, or white (non-Hispanic)."

Screening and Diagnosis Detail
AD Diagnosis:
CDR Clinical Dementia Rating (Berg 1988)
DSM IV Diagnostic and Statistical Manual IV
NINCDS ADRDA National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association Criteria (McKhann 1984)
Neuropsychological examination

Total Dementia Definition: Dementia via DSM-IV clinical criteria and CDR >1

"Dementia diagnosis and specific cause assignment was made by consensus of two neurologists, one psychiatrist, and two neuropsychologists based on baseline and follow-up information that included the neuropsychological history, medical history, assessment of function, and neurological examination. Brain imaging was not used for dementia diagnosis. Dementia diagnosis was based on Diagnostic and Statistical Manual of Mental Disorders
(DSM)-IV criteria and required evidence of cognitive deficit on neuropsychological testing and evidence of social or occupational function impairment (CDR > 1), AD diagnosis was based on NINCDS-ADRDA criteria. A diagnosis of probable AD was made when dementia could not be explained by other disorders. A diagnosis of possible AD was made when the most likely cause of dementia was AD, but there were other disorders that could contribute such as stroke."

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

"Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95% CI for the association between MeSy [Metabolic Syndrome](NCEP-criteria), and its separate risk factors, and the risk of incident AD, DAS, and all-cause dementia. ... The time-to-event variable was the age at dementia onset, to interpret the hazard function as the age-specific incidence of the disease. Secondary analyses were done with follow-up as the time-to-event variable. Individuals who did not develop the outcome of interest, died, or were lost to follow-up were censored at the time of their last evaluation. Individuals with dementia not caused by the subtype of interest were censored at the time of dementia onset. The proportional hazards assumption was checked using a log versus log minus log plot. Analyses were repeated within strata of sex, ethnicity, APOE-genotype, and cohort. Secondary analyses were done excluding subjects with prevalent cognitive impairment."

AD Covariates:
Aage
Eeducation
Ggender
APOE4APOE e4 genotype
RErace/ethnicity
SMsmoking status

TD Covariates:
Aage
Eeducation
Ggender
APOE4APOE e4 genotype
RErace/ethnicity
SMsmoking status