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AlzRisk Paper Detail

Reference: Kawas, 1997
Cohort: Baltimore Longitudinal Study of Aging
Risk Factor: Hormone Therapy

Average Follow-up Time Detail
The paper only reports that women were followed for a maximum of 16 years. There is no information on average follow-up time.

Exposure Detail
Estrogen usage was assessed via questionnaire at biennial follow-up visits. Women were considered ERT users if they had ever used oral (95%) or transdermal estrogens (5%). Pre-menopausal estrogren use and use of estrogen cream was excluded. The paper does not provide details about the percentage of women who used unopposed estrogen v. estrogen combined with progestin.

Exposure use was categorized in terms of 1) history of estrogen use (ever v. never), and 2) duration of use (0 to 5 years, > 5 to 10 years, > 10 years). Results reported in this table are for duration of use.

Total duration of ERT use was defined as a categorical variable: no use, > 0 to 5 years, 5 to 10 years, and > 10 years. Subjects were assigned the midpoint of the interval as the duration of exposure (e.g., those who reported 1 to 5 years of use were assigned 3 years of use). The exposure distribution is not reported.

Screening and Diagnosis Detail
AD Diagnosis:
Brain Imaging
DSM IIIR Diagnostic and Statistical Manual III-Revised
NINCDS ADRDA National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association Criteria (McKhann 1984)
Neurologic examination

The authors do not discuss the specific screening procedure, but report the following information about information collected at biennial visits:

"Every 2 years, subjects returned to the Gerontology Research Center (GRC/NIA) for 2.5 days of multidisciplinary evaluations that included medical history, medication usage (including estrogens), physical and neurologic examinations, neuropsychological and functional assessments, and numerous other physiologic and psychological procedures."

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

Of the 514 eligible women, 472 had ERT data and were included in the analyses.

Education was modeled as a binary variable (greater than or equal to 16 years v. less than 16 years).

AD Covariates:

The authors examined the effects of age at menopause, age at menarche, years of natural cyclic estrogen exposure, duration of menopause, and surgical menopause, but these variables did not effect the results and education and age were the only covariates included in the final analysis.