Lj. Launer et al., Rates and risk factors for dementia and Alzheimer's disease - Results fromEURODEM pooled analyses, NEUROLOGY, 52(1), 1999, pp. 78-84
Objective: To investigate the risk of AD associated with a family history o
f dementia, female gender, low levels of education, smoking, and head traum
a. Background: These putative factors have been identified in cross-section
al studies. However, those studies are prone to bias due to systematic diff
erences between patients and control subjects regarding survival and how ri
sk factors are recalled. Methods: The authors performed a pooled analysis o
f four European population-based prospective studies of individuals 65 year
s and older, with 528 incident dementia patients and 28,768 person-years of
follow-up. Patients were detected by screening the total cohort with brief
cognitive tests, followed by a diagnostic assessment of those who failed t
he screening tests. Dementia was diagnosed with the Diagnostic and Statisti
cal Manual of Mental Disorders, 3rd ed. (revised), and AD was diagnosed acc
ording to National Institute of Neurological and Communicative Disorders an
d Stroke-Alzheimer's Disease and Related Disorders Association criteria. In
cident rates and relative risk. (95% CI) express the association of a risk
factor far dementia. Results: Incident rates for dementia and AD were simil
ar across studies. The incidence of AD increased with age. At 90 years of a
ge and older the incidence was 63.5 (95% CI, 49.7 to 81.0) per 1,000 person
-years. Female gender, current smoking (more strongly in men), and low leve
ls of education (more strongly in women) increased the risk of AD significa
ntly. A history of head trauma with unconsciousness and family history of d
ementia did not increase risk, significantly. Conclusion: Contrary to previ
ous reports, head trauma was not a risk factor for AD, and smoking did not
protect against AD. The association of family history with the risk of AD i
s weaker than previously estimated on the basis of cross-sectional studies.
Female gender may modify the risk. of AD, whether it be via biological or
behavioral factors.