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Reference: Sundelof, 2009a
Cohort: Uppsala Longitudinal Study of Adult Men
Risk Factor: Inflammatory Biomarkers


Average Follow-up Time Detail
Follow-up was defined as the time from the baseline examination to the date of diagnosis of AD, the date of diagnosis of any other cognitive impairment making the subsequent diagnosis of AD impossible, the date of death, the date of move away from Uppsala county (n=16), or the end of the follow-up period on December 31, 2005.

In this study, the investigators were working with two cohorts defined by age at baseline, each of which contributes a row to this table. This entry reflects consideration of the 1062 participants who were approximately 70 years old at baseline.

The median follow-up from the age 70 examination was 11.3 years (range 1.01-14.3 years).

Exposure Detail
"High sensitivity IL-6 was analyzed by an ELISA kit (IL-6 HS, R&D Systems, Minneapolis, MN). Samples and standards were pipetted in a microtiter plate coated with monoclonal antibody against IL-6. After incubation, a washing enzyme substrate solution was pipetted and followed by anti-IL-6 antibody. The color reaction was proportional to the bound IL-6. The total CV of the method was 7% and the interassay CV was 5%."

In their original report, the authors reported serum IL-6 levels in units of mg/L. However, this was a typographical error, and the units were, in fact, pg/mL (J. Sundelöf, personal communication, March 30, 2010).

Ethnicity Detail
All participants were residents of Uppsala, Sweden.

Age Detail
The authors stratified results by age at baseline. This entry summarizes the results for those who were age 70 at baseline.

Screening and Diagnosis Detail
Screening Method:
MMSEMini-Mental State Examination (Folstein 1975)
Other

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

Screening: (Described in Sundelof et al. 2008) "Subjects with low test performance (Mini-Mental State Examination [MMSE] score < 26; or at age 82 years, MMSE score <+u>< 26 and/or 7-minute screen = high risk), were referred to the Geriatric Memory Clinic at the Uppsala University Hospital for a thorough clinical assessment. Further, all available medical records from the Uppsala University Hospital, all general practitioners in Uppsala (private and/or public), and all community nursing homes and dementia group living settings were reviewed on all subjects (n = 1,153) from 1990 up to December 31, 2005, regardless of the results on the cognitive screening."

Total dementia definition: All-cause dementia cases included cases with:
(1) AD (defined with NINCDS-ADRDA and DSM-IV criteria), (2) AD and cerebral vascular disease (AD+CVD) (defined as AD cases with <= 2 clinically silent brain infarctions, (3) vascular dementia (VaD) (defined with Chui criteria[29]), and (4) dementia not otherwise specified (NOS).

Covariates & Analysis Detail
Analysis Type:
Cox proportional hazards regression

Levels of IL-6 were evaluated as both continuous and categorical variables (above or below/at the median). This table reports the results for IL-6 treated as a continuous variable.

AD Covariates:
Aage
Eeducation
AIManti-inflammatory medication
APOE4APOE e4 genotype
ASPaspirin
BMIbody mass index
DMdiabetes mellitus
HTNhypertension
SCHserum cholesterol
SMsmoking status
SHstroke history

TD Covariates:
Aage
Eeducation
AIManti-inflammatory medication
APOE4APOE e4 genotype
ASPaspirin
BMIbody mass index
DMdiabetes mellitus
HTNhypertension
SCHserum cholesterol
SMsmoking status
SHstroke history