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AlzRisk Paper Detail

Reference: Masaki, 2000
Cohort: Honolulu-Asia Aging Study
Risk Factor: Nutritional Antioxidants

Average Follow-up Time Detail
No specific follow-up time provided. Investigators assessed participants' supplement use in 1988 and then evaluated them for AD and other dementias from 1991 to 1993.

Exposure Detail
"Participants in the 1988 mailed survey were asked whether they had taken multivitamins or additional vitamin A, C, or E pills in the prior year. Those responding affirmatively were asked the number of pills taken each week. Subjects were defined as C and E supplement users when the number of these pills taken each week was greater than zero. Dosage information was not available for this analysis. The number of subjects reporting the use of vitamin A supplements was too small to allow meaningful analysis. For the analyses presented here, we divided the population into four mutually exclusive groups: the first group included those taking neither vitamin C nor E (n=2102, reference), the second group took only vitamin C (n=388), the third group took only vitamin E (=189), and the fourth group took both vitamin C and E supplements (n=706). Although multivitamin use was reported by individuals in all four groups, this information was ignored because most multivitamin preparations then available contained relatively low doses of vitamin C and E."

Important note: This table includes results for only 2 categories of vitamin E use due to the exclusion of participants who used any vitamin C. Therefore, the percents shown do not add up to 100%.

Ethnicity Detail
Japanese men living in Hawaii.

Age Detail
Ages reported corresponded to the period in which the men were evaluated for dementia (1991-1993) and not the age in which they were assessed for vitamin E use (1988).

Screening and Diagnosis Detail
Screening Method:
CASICognitive Abilities Screening Instrument (Teng 1994)
CERADConsortium to Establish a Registry for Alzheimer's Disease (Morris 1989)
Informant interview

AD Diagnosis:
NINCDS ADRDA National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association Criteria (McKhann 1984)

"Dementia case finding occurred in three phases, and details have been published elsewhere (3). Phase I included 3,734 men who received cognitive screening with the Cognitive Abilities Screening Instrument (CASI) during exam IV. The CASI, developed as a brief screening cognitive assessment test for comparative studies in Asian and American populations, includes tests of nine domains of cognitive function (attention, concentration, orientation, short and long-term memory, language ability, visual construction, word list generation, abstraction, and judgment), and the score ranges from 0 (worst) to 100 (best score)(29). All men with a CASI score less than 74 and all men age 85 years or older, together with a stratified probability sample of those less than 85 years of age and with a CASI score equal to or greater than 74 were selected for phase II. The phase II examination included a second CASI examination and an informant interview, and was completed by 89% (n=948) of those invited. Participants with persistently low CASI scores (better of two scores <75) or an informant interview suggestive of cognitive decline, together with a probability sample of the remaining phase II participants, were invited to return for a comprehensive neurologic and neuropsychological evaluation (phase III), which included the Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological test battery (30,31) and a neurologic examination by a neurologist with advanced training in behavioral neurology. Phase III had an 84% response rate. Of the 426 men who were fully evaluated, 226 met Diagnostic and Statistical Manual of Mental Disorders, 3rd edition, revised (DSM-III-R), diagnostic criteria for dementia (32). AD was diagnosed according to the criteria of the National Institute of Neurologic and Communicative Disorders and Stroke and the Alzheimer’s Disease and Related Disorders Association(33). VaD was determined by the criteria proposed by the California Alzheimer’s Disease Diagnostic and Treatment Centers (34). Mixed/other dementia included all cases of DSM-III-R-positive dementia except those with pure AD or pure VaD. This group contained a substantial number of VaD or AD patients in which another contributing or main cause for the dementia was apparent, as well as dementia cases attributed to causes other than AD or VaD. Low cognitive test scorers were defined as a phase I CASI score of less than 74 in participants who were not categorized subsequently as demented by DSM-III-R diagnostic criteria. Using the cutoff point of a CASI score , 74, the sensitivity for dementia defined by DSM-III-R was 80%, and specificity was 90%. During the fourth examination, proxy family informants were asked when the participant started to develop problems with memory and cognition. Some participants had an onset of memory problems before the mailed questionnaire in 1988. Because it is possible that these participants may have been demented in 1988, which may have affected their response to the question of vitamin supplement intake, we excluded the following subjects from the analyses: those with onset of dementia before 1988 (n=33) and those with a history of stroke and onset of dementia before 1988 (n=19). Also, participants with a CASI score of less than 74 who declined invitation to return for additional testing (n=59) were excluded from the analyses, because they may represent missed prevalent cases during the 1991 to 1993 examination. After excluding these 111 participants, the remaining 3,385 men comprised our study population."

Covariates & Analysis Detail
Analysis Type:
Logistic regression

AD Covariates:
APOE4APOE e4 genotype
SHstroke history