Collected Dataset / CSHA1_Institution

The population consists of a representative sample of people aged 65 and over on Oct. 1, 1990. Subjects were living in nursing homes, chronic care facilities or collective dwellings such as convents.

Community participants were interviewed in their homes (where the 3MS cognitive screening test was administered).

The community interview collected also social and demographic information, and assessed disability with ADL and IADL questionnaires. All subjects who scored less than 78 were invited to undergo the clinical assessment as well as a sample of those who scored 78 or over.

Dementia was diagnosed based on a combination of medical and neuropsychological assessments administered in the patient’s home or a clinic. After the physician and neuropsychologist had independently made preliminary diagnoses, they met with the nurse to reach a consensus diagnosis and classified participants as demented, cognitively impaired but not demented (“CIND”), or as cognitively normal.

Diagnostic criteria for dementia followed the Diagnostic and Statistical Manual of Mental Disorders, 3rd edition revised (DSM-III-R); for Alzheimer's disease, the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA); and a draft of the 10th revision of the International Classification of Diseases (ICD) to define subcategories of vascular and other dementias.

The examination was divided into four parts.

First, a nurse registered the subjects and completed consent forms, administered the 3MS exam, tested hearing, vision and vital signs, recorded height, weight and medication use, and obtained the subject's cognitive and family history from a relative, using section H of the Cambridge Mental Disorders of the Elderly Examination (CAMDEX).

Second, a psychometrician, blind to the 3MS score from the interview, administered neuropsychologic tests to subjects with a score of 50 or more for the 3MS exam given by the nurse. A neuropsychologist evaluated the test results in conjunction with the results of the CAMDEX and the 3MS exam administered by the nurse.

Third, a physician reviewed the information collected by the nurse and examined the patient, performing a mental status assessment as well as physical and neurologic examinations. The physician then made a preliminary diagnosis before seeing the neuropsychologist's evaluation.

Participants suspected of having dementia or delirium were sent for hematologic and biochemical tests.

A blood sample was collected in 9 centres.

A risk factor questionnaire for all participants was completed by the person themselves where they were cognitively able to do this, and by a proxy respondent where necessary. A proxy respondent also completed the risk factor questionnaire for a sample of cognitively normal participants who served as controls for the initial case-control risk factor analysis.