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AlzRisk Paper Detail

Reference: Plassman, 2000
Cohort: World War II Navy and Marine veterans
Risk Factor: Head injury

Average Follow-up Time Detail
Because of the historical cohort design, no exact follow-up time was available. Participants were World War
II US Navy or Marine male veterans who had served during 1944 to 1945. Abstraction of medical records occurred in 1996 to 1997, which was then followed by participant recruitment and dementia assessment.

Exposure Detail
History of head injury was ascertained from a review of military medical records.

"Trained staff abstracted the military
medical records for information about the head
injuries, including cause of injury and duration of loss of
consciousness or post-traumatic amnesia. Men were then
considered “exposed” if they had experienced head trauma
that 1) was documented in the military medical records,
2) occurred during military service, 3) produced loss of
consciousness, post-traumatic amnesia, or skull fracture,
4) did not penetrate the dura mater, and 5) did not result
in marked cognitive impairment or neurologic sequelae
more than 3 months post-trauma."

The severity of the head injuries were also categorized as follows: "1) mild injury 5 loss of consciousness or post-traumatic amnesia for less than 30 minutes, with no skull fracture; 2) moderate injury 5 loss of consciousness or post-traumatic amnesia for more than 30 minutes but less than 24 hours, and/or a skull fracture; and 3) severe injury 5 loss of consciousness or post-traumatic amnesia for more than 24 hours."

Age Detail
Age at start of follow-up was not available

Screening and Diagnosis Detail
Screening Method:
DQDementia Questionnaire (Silverman 1986)
IQ-CODEInformant Questionnaire for Cognitive Decline in the Elderly (Jorm 1989)
TICSTelephone Interview of Cognitive Status

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.

Men with dementia were identified in three stages. First, the TICS was administered, or the IQ-CODE to an informant when the participant was unable to be tested. Men with an
education-adjusted TICS score of less than 29 or an
IQCODE score above 3.2719 were then screened using the Dementia Questionnaire (DQ). Men whose DQ results suggested dementia to then underwent a clinical assessment administered by a research nurse and psychometrician. Diagnoses of AD were made using NINCDS-ADRDA criteria by aboard-certified geriatric psychiatrist, a cognitive neuroscientist, and the assessment team.

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

Cox proportional hazards regression with age as the time scale was used.

AD Covariates:

TD Covariates: