The role of APOE-epsilon4 in longitudinal cognitive decline: MacArthur Studies of Successful Aging.
BACKGROUND
While a genetic risk factor for late-onset AD, the effects of the epsilon4 allele of the APOE gene on cognitive functioning more generally remain unclear.


OBJECTIVE
To assess the role of the epsilon4 allele of the APOE gene in longitudinal cognitive decline.


METHODS
Multiple measures of cognitive function were assessed longitudinally in the MacArthur Successful Aging Study, a population-based cohort free of frank impairment at baseline. Subjects were 965 Caucasian and African American men and women from Durham NC, East Boston, MA, and New Haven, CT, aged 70 to 79 years, recruited in 1988 through 1989, who completed two follow-up evaluations, one at 3 years and another at 7 years.


RESULTS
At the first follow-up, modest but significant declines in naming and spatial ability were associated with the APOE-epsilon4 genotype. By the second follow-up, more pronounced and significant associations were noted between the APOE-epsilon4 genotype and cognitive decline from six of the eight cognitive outcomes. After 7 years, APOE-epsilon4 allele carriers were twice as likely to have declined on a global cognitive score (odds ratio = 2.0; 95% CI: 1.1, 3.6) as noncarriers.


CONCLUSIONS
APOE-epsilon4 is associated with cognitive decline among a high-functioning elderly cohort, with effects most pronounced after 7 years of follow-up. Hence, the epsilon4 allele either may function as a risk factor for cognitive impairment in normal aging across a broad spectrum of domains or may exert detectable effects early in a long prodromal AD trajectory.
Bretsky
P
P
Department of Preventive Medicine, Keck School of Medicine, USC/Norris Comprehensive Cancer Center, Los Angeles, CA 90033, USA. pbretsky@usc.edu
Guralnik
J M
JM
Launer
L
L
Albert
M
M
Seeman
T E
TE
D000368:Aged; D000375:Aging / Q000235:genetics*; D000483:Alleles; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics*; D044383:Black People / Q000235:genetics; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D015331:Cohort Studies; D003710:Demography; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005787:Gene Frequency; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016017:Odds Ratio; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D044465:White People / Q000235:genetics; D001741:Black or African American
D053327:Apolipoprotein E4; D001057:Apolipoproteins E