Multimorbidity and Risk of Mild Cognitive Impairment
Multimorbidity and Risk of Mild Cognitive Impairment
Objectives: To determine the association between multiple chronic conditions and risk of incident mild cognitive impairment (MCI) and dementia.
Design: Prospective cohort study.
Setting: Olmsted County, Minnesota.
Participants: Cognitively normal individuals (N = 2,176) enrolled in the Mayo Clinic Study of Aging (MCSA).
Measurements: Participants were randomly selected from the community, evaluated by a physician, and underwent neuropsychometric testing at baseline and at 15-month intervals to assess diagnoses of MCI and dementia. Information on International Classification of Diseases, Ninth Revision codes for chronic conditions in the 5 years before enrollment was electronically captured using the Rochester Epidemiology Project medical records linkage system. Multimorbidity was defined as having two or more chronic conditions, and the association between multimorbidity and MCI and dementia was examined using Cox proportional hazards models.
Results: Of 2,176 cognitively normal participants (mean age ± standard deviation 78.5 ± 5.2; 50.6% male), 1,884 (86.6%) had multimorbidity. The risk of MCI or dementia was higher in persons with multimorbidity (hazard ratio (HR) = 1.38, 95% confidence interval (CI) = 1.05–1.82) than in those with one or no chronic condition. The HR was of greater magnitude in persons with four or more conditions (HR = 1.61, 95% CI = 1.21–2.13) than in those with two or three conditions (HR = 1.03, 95% CI = 0.76–1.39) and for men with multimorbidity(HR = 1.53, 95% CI = 1.01–2.31) than for women with multimorbidity (HR = 1.20, 95% CI = 0.83–1.74), compared to those with one or no chronic condition.
Conclusion: In older adults, having multiple chronic conditions is associated with greater risk of MCI and dementia. This is consistent with the hypothesis that multiple etiologies may contribute to MCI and late-life dementia. Preventing chronic diseases may be beneficial in delaying or preventing MCI and dementia.
Multimorbidity, defined as the coexistence of two or more chronic conditions in an individual, is highly prevalent in older adults. Estimates of prevalence increase with age and range from 55% to 98% in populations aged 60 and older. Advances in the management of chronic conditions have resulted in slower disease progression and delayed mortality, resulting in an increase in the prevalence of multimorbidity. The risk of disability, functional decline, premature death, poor quality of life, polypharmacy, more medical consultations, more hospitalizations, longer hospital stays, greater use of emergency care, and higher healthcare costs are all greater in individuals with multimorbidity. Certain chronic conditions may also enhance the development of additional chronic conditions.
With the growing number of individuals aged 65 and older in the United States and worldwide, the implications of the effect of multimorbidity on risk of age-related conditions such as mild cognitive impairment (MCI) and dementia are highly relevant for public health planning, allocation of resources, and development of strategies to reduce risk of these conditions. In particular, multimorbidity may contribute to greater risk of MCI, an important precursor to Alzheimer's disease and other dementias, but the association has not been comprehensively investigated in a population-based setting. The primary objective of this study was to determine the association between multimorbidity and incident MCI and dementia in a cohort of cognitively normal individuals enrolled in the prospective population-based Mayo Clinic Study of Aging (MCSA).
Abstract and Introduction
Abstract
Objectives: To determine the association between multiple chronic conditions and risk of incident mild cognitive impairment (MCI) and dementia.
Design: Prospective cohort study.
Setting: Olmsted County, Minnesota.
Participants: Cognitively normal individuals (N = 2,176) enrolled in the Mayo Clinic Study of Aging (MCSA).
Measurements: Participants were randomly selected from the community, evaluated by a physician, and underwent neuropsychometric testing at baseline and at 15-month intervals to assess diagnoses of MCI and dementia. Information on International Classification of Diseases, Ninth Revision codes for chronic conditions in the 5 years before enrollment was electronically captured using the Rochester Epidemiology Project medical records linkage system. Multimorbidity was defined as having two or more chronic conditions, and the association between multimorbidity and MCI and dementia was examined using Cox proportional hazards models.
Results: Of 2,176 cognitively normal participants (mean age ± standard deviation 78.5 ± 5.2; 50.6% male), 1,884 (86.6%) had multimorbidity. The risk of MCI or dementia was higher in persons with multimorbidity (hazard ratio (HR) = 1.38, 95% confidence interval (CI) = 1.05–1.82) than in those with one or no chronic condition. The HR was of greater magnitude in persons with four or more conditions (HR = 1.61, 95% CI = 1.21–2.13) than in those with two or three conditions (HR = 1.03, 95% CI = 0.76–1.39) and for men with multimorbidity(HR = 1.53, 95% CI = 1.01–2.31) than for women with multimorbidity (HR = 1.20, 95% CI = 0.83–1.74), compared to those with one or no chronic condition.
Conclusion: In older adults, having multiple chronic conditions is associated with greater risk of MCI and dementia. This is consistent with the hypothesis that multiple etiologies may contribute to MCI and late-life dementia. Preventing chronic diseases may be beneficial in delaying or preventing MCI and dementia.
Introduction
Multimorbidity, defined as the coexistence of two or more chronic conditions in an individual, is highly prevalent in older adults. Estimates of prevalence increase with age and range from 55% to 98% in populations aged 60 and older. Advances in the management of chronic conditions have resulted in slower disease progression and delayed mortality, resulting in an increase in the prevalence of multimorbidity. The risk of disability, functional decline, premature death, poor quality of life, polypharmacy, more medical consultations, more hospitalizations, longer hospital stays, greater use of emergency care, and higher healthcare costs are all greater in individuals with multimorbidity. Certain chronic conditions may also enhance the development of additional chronic conditions.
With the growing number of individuals aged 65 and older in the United States and worldwide, the implications of the effect of multimorbidity on risk of age-related conditions such as mild cognitive impairment (MCI) and dementia are highly relevant for public health planning, allocation of resources, and development of strategies to reduce risk of these conditions. In particular, multimorbidity may contribute to greater risk of MCI, an important precursor to Alzheimer's disease and other dementias, but the association has not been comprehensively investigated in a population-based setting. The primary objective of this study was to determine the association between multimorbidity and incident MCI and dementia in a cohort of cognitively normal individuals enrolled in the prospective population-based Mayo Clinic Study of Aging (MCSA).
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