The Effect of Maintaining Cognition on Risk of Disability and Death

Authors

  • Kristine Yaffe MD,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • Karla Lindquist MS,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • Eric Vittinghoff PhD, MPH,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • Deborah Barnes PhD,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • Eleanor M. Simonsick PhD,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • Anne Newman MD, MPH,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • Suzanne Satterfield MD, DrPH,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • Caterina Rosano MD, MPH,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • Susan M. Rubin MPH,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • Hilsa N. Ayonayon PhD,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • Tamara Harris MD, MS,

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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  • for the Health, Aging and Body Compsition Study

    1. From the Departments of *Psychiatry, Neurology, Epidemiology and Biostatistics, and Medicine, School of Medicine, University of California at San Francisco, San Francisco, California; §San Francisco Veterans Affairs Medical Center, San Francisco, California; #Intramural Research Program, National Institute on Aging, Baltimore, Maryland; **Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania; ††Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee; and ‡‡Department of Epidemiology, Demography and Biometry Program, National Institute on Aging, Bethesda, Maryland.
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Address correspondence to Kristine Yaffe, c/o University of California, San Francisco, Box 181, 4150 Clement Street, San Francisco, CA 94121. E-mail: kristine.yaffe@ucsf.edu

Abstract

OBJECTIVES: To determine whether long-term maintenance of cognition is associated with health advantages such as lower mortality or incident disability in older adults.

DESIGN: Longitudinal cohort study.

SETTING: Community clinics at two sites.

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

MEASUREMENTS: 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 ≥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 ɛ4, 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.

CONCLUSION: 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.

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