The effect of maintaining cognition on risk of disability and death.
OBJECTIVE
To determine whether long-term maintenance of cognition is associated with health advantages such as lower mortality or incident disability in older adults.


METHODS
Longitudinal cohort study.


METHODS
Community clinics at two sites.


METHODS
Two thousand seven hundred thirty-three adults with a mean age of 74 at baseline and 80 at follow-up.


METHODS
Cognitive function was assessed using the Modified Mini-Mental State Examination (3MS), a test of global cognition, at least two times. Three cognitive groups were defined based on 4-year participant-specific slopes (maintainers, slopes of >or=0; minor decliners, slopes <0 but no more than 1 standard deviation (SD) below the mean; major decliners, slopes >1 SD below the mean). Whether the cognitive groups differed in mortality and incident disability during the subsequent 3 years was determined.


RESULTS
Nine hundred eighty-four (36%) participants were maintainers, 1,314 (48%) were minor decliners, and 435 (16%) were major decliners. Maintainers had lower mortality (7% vs 14%, hazard ratio (HR)=0.48, 95% confidence interval (CI)=0.36-0.63) and incident disability (22% vs 29%, HR=0.74, 95% CI=0.62-0.89) than minor decliners. After adjustment for age, race, sex, education, apolipoprotein E epsilon4, depression, body mass index, stroke, hypertension, and diabetes mellitus, these differences remained. As expected, major decliners had greater mortality (20%) and incident disability (40%) than minor decliners.


CONCLUSIONS
A substantial proportion of older adults maintain cognitive function in their eighth and ninth decades of life. These older adults demonstrate lower risk of death and functional decline than those with minor cognitive decline, supporting the concept of "successful" cognitive aging.
Yaffe
Kristine
K
Department of Psychiatry, University of California at San Francisco, San Francisco, California 94121, USA. kristine.yaffe@ucsf.edu
Lindquist
Karla
K
Vittinghoff
Eric
E
Barnes
Deborah
D
Simonsick
Eleanor M
EM
Newman
Anne
A
Satterfield
Suzanne
S
Rosano
Caterina
C
Rubin
Susan M
SM
Ayonayon
Hilsa N
HN
Harris
Tamara
T
D000368:Aged; D003071:Cognition / Q000502:physiology*; D015928:Cognitive Behavioral Therapy; D015331:Cohort Studies; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009026:Mortality
Arch Gerontol Geriatr. 2009 Jan-Feb;48(1):28-34
17976840
J Neurophysiol. 2006 Mar;95(3):1509-17
16338994
Dement Geriatr Cogn Disord. 2006;22(4):312-9
16940725
J Gerontol B Psychol Sci Soc Sci. 2003 May;58(3):S187-98
12730320
Nat Neurosci. 2005 Dec;8(12):1657-9
16286930
Neurobiol Aging. 2007 Feb;28(2):171-8
17097195
Alzheimer Dis Assoc Disord. 1999 Jul-Sep;13(3):176-81
10485578
Am J Med Genet B Neuropsychiatr Genet. 2010 Jan 5;153B(1):114-9
19367585
Psychol Aging. 2007 Mar;22(1):134-146
17385990
Neurology. 2003 May 13;60(9):1489-94
12743237
Neurology. 2009 Jun 9;72(23):2029-35
19506226
J Am Geriatr Soc. 2002 Jun;50(6):1045-50
12110064
J Am Geriatr Soc. 2008 Nov;56(11):2082-8
18795984
Int J Geriatr Psychiatry. 2006 Apr;21(4):356-62
16534773
Science. 1987 Jul 10;237(4811):143-9
3299702
Neuroepidemiology. 2007;29(3-4):226-34
18073495
Psychol Aging. 1999 Sep;14(3):365-79
10509693
J Am Geriatr Soc. 2007 Feb;55(2):259-64
17302664
Aust N Z J Public Health. 1998 Aug;22(5):621-3
9744220
Psychol Aging. 2002 Jun;17(2):179-93
12061405
Sci Aging Knowledge Environ. 2004 Jun 09;2004(23):pe26
15190177
Ann Neurol. 2006 Dec;60(6):688-95
17192929
J Clin Psychiatry. 1987 Aug;48(8):314-8
3611032