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AlzRisk Paper Detail

Reference: Chiang, 2007
Cohort: Multiple Risk Factors for Major Diseases cohort & Cancer Screening Program cohort
Risk Factor: Obesity

Average Follow-up Time Detail
The MRMD cohort recruited participants between 1982 and 1986 while the CSP cohort recuited participants between 1991 and 1992. Dementia cases are defined as those with a diagnosis of dementia according to national records at any time between 2000 and 2002.

Exposure Detail
Method of ascertaining BMI: structured interviews

Interviews were based on structured questionnaires. Body mass index was calculated as weight (in kilograms)divided by height (in meters)squared.

The authors evaluated effect estimates for the overall population and after restricting the study population to smokers or non-smokers. The results given in this row corresponds to non-smokers only.

Ethnicity Detail
The investigators conducted this study on a Chinese population in Taiwan.

Age Detail
Entry criteria required participants to be at least 30 years old at baseline.

Screening and Diagnosis Detail
Screening Method:

AD Diagnosis:
DSM IV Diagnostic and Statistical Manual IV

Total Dementia Definition: Dementia via DSM-IV clinical criteria

"The dementia cases were identified through a two stage method using the health insurance database linkage (stage I) and clinical confirmation by neurologists or psychiatrists (stage II). At stage I, cases of dementia were ascertained by computerized linkage with the National Health Insurance Database in Taiwan for the period from January 2000, through December 2002. Dementia diagnoses included senile dementia, AD and VaD (International Classification of Diseases, Ninth Revision codes of 290, 290.0, 290.1, 290.2, 290.3, 290.4, 294.8, 331.0). At stage II, the clinically diagnosed form of dementia was further validatedby board certificated neurologists or psychiatrists in the 48 hospitals nationwide where the patients were diagnosed. Diagnoses of dementia and subtype were based on reviews of medical charts and neuroimaging records following a common protocol of detailed evaluation of clinical information and neurobehavior with a diagnostic accuracy of approximately 90%. The Chinese version of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM–IV) was used as the standard. Demented cases were classified into four subtypes: AD, VaD, mixed types of AD and VaD (MD), and other dementia of uncertain or unclassified type. All cases were reviewed and reconfirmed by one of the principal investigators (PKY, senior neurologist specializing in dementia research)."

Covariates & Analysis Detail
Analysis Type:
Conditional logistic regression

"Four matched comparison cases were selected for each dementia case from cohort participants alive after January 2000 and unaffected with dementia. Dementia cases and comparison cases were matched by age at enrollment (five-year intervals), gender, residential township, and time of enrollment (within six months)"

These results were computed for non-smokers only.

Potential confounders with a p-value of <0.15 in univariate analyses were included in multivariate models.

AD Covariates:
CBVDcerebrovascular disease
RESresidential township
TENtime of enrollment

TD Covariates:
CBVDcerebrovascular disease
RESresidential township
TENtime of enrollment