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AlzRisk Paper Detail
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Reference: Zylberstein, 2011
Cohort: Cohort of women in Gothenburg
Risk Factor: Homocysteine


Average Follow-up Time Detail
The investigators followed this cohort for 35 years (from 1968 to 2003) until the date of last follow-up examination, date of death, December 31, 2003 (end of study), or time of dementia onset. The number of years per person of follow-up was not given. At the final follow-up, 71% of the surviving members of the initial cohort participated.

Exposure Detail
The following was taking from Zyberstein et al 2011:

"The original survey (Bengtsson et al.,1973) included fasting blood sampling aimed both for immediate and future
analyses. Approximately 120 ml blood was drawn from each
study subject. A small part of the blood at the baseline examination was used for the initial analyses and the rest was allowed to clot in room temperature for 2–3 h. After centrifugation the serum was stored at −20 Celsius in 2.5 ml covered polystyrene cups enclosed together in small batches,in firmly tied plastic bags. The original frozen samples in the present study were stored for 28 years at −20 Celsius, thawed once for other analyses and restored for 2 years at −80 Celsius. Stability of tHcy in longtime stored samples has been previously reported by other investigators (Israelsson etal.,1993).

Total tHcy was determined in all the original serum
samples by the Abbott IMX homocysteine assay(Abbot Lab-
oratories, Abbot Park,IL,USA). We have reported close
agreement between previously thawed vs.non-thawed samples
regarding tHcy (Zylberstein etal.,2004.)".

Ethnicity Detail
No additional information about ethnicity was given.

Age Detail
All participants were between 38 and 60 years old at the time of recruitment, i.e., 1968. The average age at baseline was 46.8 years.

Screening and Diagnosis Detail
Screening Method:
CDRClinical Dementia Rating (Berg 1988) (CDR)
Informant interview
IQ-CODEInformant Questionnaire for Cognitive Decline in the Elderly (Jorm 1989)
MMSEMini-Mental State Examination (Folstein 1975)
Neuropsych Testing
Other

AD Diagnosis:
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)

Examinations also included the Comprehensive Psychopathological Rating Scale, Gottfries–Bråne–Steen Scale, and the Alzheimer’s Disease Assessment Scale(ADAS-Cog).

Geriatric psychiatrists made diagnoses of dementia for those lost-to-follow-up by accessing medical records and the Swedish Hospital Discharge Registry.

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

Investigators computed HRs using Cox-Proportional Hazards regression, and comparing the highest and the second highest tertiles of exposure to the lowest. Exposure was also modeled as a continuous variable, but the results were not provided.

AD Covariates:
Aage
Eeducation
BMIbody mass index
DBPdiastolic blood pressure
CRTserum creatinine
SMsmoking status
SBPsystolic blood pressure
TCtotal cholesterol
TGtriglycerides
VTBvitamin B12

TD Covariates:
Aage
Eeducation
BMIbody mass index
DBPdiastolic blood pressure
CRTserum creatinine
SMsmoking status
SBPsystolic blood pressure
TCtotal cholesterol
TGtriglycerides
VTBvitamin B12