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Reference: Petitti, 2008
Cohort: Kaiser Permanente Medical Care Program of Southern California
Risk Factor: Hormone Therapy


Average Follow-up Time Detail
Follow-up for incident dementia began on July 1, 1998, and continued through December 31, 2003.

Exposure Detail
Computer-stored prescription data (beginning in 1992) was used to define hormone therapy users and non-users. Hormone therapy users were defined as women who had filled at least one prescription for oral estrogen at a health plan pharmacy in every calendar year from 1992 to 1998. Non-users were defined as women with no prescriptions for hormone therapy between 1992 and 1998. Women with intermittent prescriptions between 1992 and 1998 were not eligible. Information about when hormone therapy started and age at menopause was available only by self-report.

The results reported in this table compare AD risk in hormone therapy users (classified by formulation, i.e., with or without progestin) to non-users.

Age Detail
The mean age reported here is age at baseline.

Screening and Diagnosis Detail
Screening Method:
Informant interview
Other
TICS-mTelephone Interview of Cognitive Status - modified (Plassman 1994)

AD Diagnosis:
Other

Diagnosis of dementia occurred in three stages:

"In the first stage, the TICSm (27) was administered.
Women with a TICSm score greater than 27 were classified
as having 'no or minimal cognitive impairment' for that year. Women with a TICSm score of 27 or less were selected for the second stage of assessment, wherein the Telephone Dementia Questionnaire (TDQ) (30) was administered to a proxy."

"The TDQ results were reviewed independently by three investigators, who were blinded to hormone use. A predefined protocol was used to classify the second-stage TDQ result: no or minimal impairment, dementia, or uncertain. Classification of a woman as having dementia required memory deficits, impairment in at least two other cognitive domains, and functional impairment. The criteria for dementia in the Diagnostic and Statistical
Manual of Mental Disorders, Fourth Edition (31), require
only one other cognitive deficit in addition to memory.
More stringent classification criteria (requiring two other cognitive domains) were applied in this study because some of the cognitive domains assessed in person cannot be assessed telephonically. The independent classifications were reviewed in a consensus conference. Women with consensus classification of 'dementia' or 'no or minimal impairment' were given that classification for that interview year. Women with consensus classification of 'uncertain' at the second stage, based on the TDQ, and women with a low TICSm score for whom a proxy TDQ could not be completed proceeded to the third stage of assessment."

"In the third stage, medical records were reviewed by reviewers who were blinded to hormone therapy use. Women
were given a final classification of 'dementia' at this stage if there was a diagnosis of dementia recorded in the medical record and a classification of 'cognitive impairment but dementia uncertain' if the medical record mentioned cognitive impairment but not dementia. If there was no mention of these conditions in the medical record, the women with TDQ data were given a final classification of 'cognitive impairment but dementia uncertain' for that year. Women without a completed TDQ were given a classification for that year of 'no or minimal impairment.' Medical records were used to subclassify dementia cases according to whether the dementia had a known cause (vascular, Lewy body, Parkinson’s disease, etc.). If none of these causes were mentioned in medical records, the woman was classified as having dementia without a known cause, an approximation of Alzheimer’s disease."

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

AD Covariates:
Aage
Eeducation
DMdiabetes mellitus
HTNhypertension
MImycardial infarction history
PDParkinson's disease
SHstroke history

TD Covariates:
Aage
Eeducation
DMdiabetes mellitus
HTNhypertension
MImycardial infarction history
PDParkinson's disease
SHstroke history

"The regression models included self-reported variables found to be strongly related to dementia in the literature (age and education) and other available variables that were associated in our data set. the variables in the final, fully adjusted model were forced."