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Reference: Ozawa, 2013
Cohort: Hisayama Study
Risk Factor: Dietary Pattern


Exposure Detail
Dietary habits were self-reported at baseline using a 70-item semi-quantitative food frequency questionnaire. Nutrient intake was adjusted for energy intake by using the nutrient density method (Willett W, Stampfer MJ. Total energy intake: implications for epidemiologic analyses. Am J Epidemiol 1986; 124:17-27).

Reduced rank regression was used to identify linear combinations (in the form of dietary pattern scores) of 19 food groups most predictive of seven nutrients reported to be related to dementia risk from previous literature. Nutrients included those believed to be protective against cognitive decline (monounsaturated fatty acids, polyunsaturated fatty acids, vitamin C, potassium, calcium, and magnesium) and those believed to be harmful (saturated fatty acids). Scores for the dietary pattern most predictive of the seven nutrients were categorized into quartiles.

Ethnicity Detail
All participants were residents of Hisayama, Japan. No other information on ethnicity or race has been reported.

Screening and Diagnosis Detail
Screening Method:
HDSHasegawa's dementia scale
HDS-RHasegawa's dementia scale - revised
MMSEMini-Mental State Examination (Folstein 1975)

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: Dementia via DSM-III-R.

"When a subject was suspected to have new neurologic
symptoms, including cognitive impairment, the subject was
carefully evaluated by the study physician and psychiatrist, who conducted comprehensive investigations including interviews of the family or attending physician, physical and neurologic examinations, and a review of the clinical records. Furthermore, when a subject died, we reviewed all available clinical information, interviewed the attending physician and the family of the deceased subject, and tried to obtain permission for an autopsy from the family. [...] The guidelines of the Diagnostic and Statistical Manual of
Mental Disorders, Revised Third Edition, were used for defining the diagnosis of dementia (15)."

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

AD Covariates:
Aage
Eeducation
Ggender
BMIbody mass index
Kcalcaloric intake
DMdiabetes mellitus
HTNhypertension
PAphysical activity
SMKHsmoking habits
SHstroke history
TCtotal cholesterol

TD Covariates:
Aage
Eeducation
Ggender
BMIbody mass index
Kcalcaloric intake
DMdiabetes mellitus
HTNhypertension
PAphysical activity
SMKHsmoking habits
SHstroke history
TCtotal cholesterol