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AlzRisk Paper Detail
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Reference: Beydoun, 2008
Cohort: Baltimore Longitudinal Study of Aging
Risk Factor: Obesity


Exposure Detail
The authors evaluated the effect estimates for men and women of different five year age categories separately. This row corresponds to men between 40 and 45 years of age.

Method of exposure ascertainment: technician measurement

"Waist circumference was defined as the minimal abdominal
perimeter located halfway between the rib cage and
the pelvic crest and was measured using a flexible tape (30)"

"Linear mixed models were fitted to sample 1 (n = 3,005
subjects) to estimate predicted values of BMI and waist circumference at ages 30, 35, 40, 45, and 50 years, using age at visit as the time variable (the method is described in Web Appendix 1, presented on the Journal’s website (http://aje.oxfordjournals.org/))".

"Predicted values for waist circumference were
categorized into quintiles, while change in waist circumference was grouped similarly to BMI change."

Age Detail
"Subjects entered follow-up at age 30 years, were entered
into the risk set at age 50 years, and exited follow-up at first failure, defined as being diagnosed with incident AD at or beyond age 50 years or being censored at the end of followup due to death or attrition."

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)

"Subjects showing changes that indicated incident dementia
were systematically studied. Diagnoses of dementia and
dementia type were formulated during multidisciplinary
evaluations based on prospectively collected evidence using
National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer’s Disease and Related Disorders Association criteria (31). Estimation of age at AD onset was based on informant reports and history of disease-free examinations."

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

AD Covariates:
Aage
Eeducation
Ggender
RErace/ethnicity
SMsmoking status
YOByear of birth