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AlzRisk Paper Detail
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Reference: MacKnight, 2002
Cohort: Canadian Study of Health and Aging
Risk Factor: Diabetes Mellitus


Exposure Detail
Diabetes status was inferred from a number of different sources, depending on the study participant. The study included community participants, who underwent a screening interview and a subsequent clinical interview if necessary, and institutionalized participants, all of whom went directly to the clinical interview. Random laboratory testing was also used in some study participants.

The screening interview, which assessed whether further clinical assessment for cognitive impairment was required for community participants, also obtained self-reported information about specific medical conditions, including diabetes. Community participants who screened positive for cognitive impairment, a random sample of those who screened negative, and all institutionalized study participants were invited to a clinical interview. Self-reported history of diabetes, use of insulin or oral hypoglycemic drugs, and health record review were used to determine diabetes status from the clinical interview.

Random testing was also used in some study participants, with venous plasma glucose levels > 11.1 mmol/l used to identify patients as diabetic.

"At CSHA-1, diabetes was recorded from 4 sources: the screening interview (self-report), the clinical interviews (self-report supplemented by informant and/or health records), the medication list (insulin or oral hypoglycemic drugs), and laboratory testing (venous plasma glucose levels > 11.1 mmol/l). Not all data were collected for every subject in CSHA-1; the first 3 sources were available for 1542 subjects, 696 of whom also had random plasma glucose levels determined."

Ethnicity Detail
The cohort is a representative sample of Canadian men and women aged 65 and older living in urban and rural Canada from all 10 provinces. More details are available here.

Screening and Diagnosis Detail
Screening Method:
3MSEModified Mini-Mental State Examination (Teng 1987)

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-R criteria

Cognitive impairment sufficient for progression to clinical assessment was defined as a score less than 79 on the Modified Mini-Mental State Examination (3MS). A random sample of those who screened negative were also invited for clinical assessment. "The clinical examination consisted of a repeat 3MS, the informant portion of the CAMDEX, a clinical examination by a physician, and neuropsychological testing. Neuroimaging was performed where indicated. A final diagnosis was made following a consensus conference. Alzheimer's disease was diagnosed using the NINCDS-ADRDA criteria."

Covariates & Analysis Detail
Analysis Type:
Logistic regression

AD Covariates:
Aage
Eeducation
Ggender

TD Covariates:
Aage
Eeducation
Ggender