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Promising Predictors of Cognitive Decline
Psychogeriatrics
Promising Predictors of Cognitive Decline
Professor, Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Director, Division of Geriatric Psychiatry, Montefiore Medical Center
First published in Psychiatry Weekly, Volume 6, Issue
2, on January 31, 2011
Peterson and colleagues reviewed biomarkers that might be useful predictors from a pre-symptomatic state to the earliest signs of mild cognitive impairment. These included spinal fluid assays of amyloid components and tau, imaging procedures for amyloid plaques, functional and structural brain changes, and measures of cognitive performance. Many of these are incorporated in the Alzheimer’s Disease Neuroimaging Initiative, which is designed to assess the value of biomarkers and imaging in predicting progression of mild cognitive impairment to Alzheimer’s disease.1
The presence of the apolipoprotein E e4 allele is a biomarker with the strongest known association for Alzheimer’s risk. Once the presence of this risk factor is verified, however, it cannot be modified.2 There are other risk factors, however, with low to moderate associations with developing cognitive decline or Alzheimer’s disease. Hypercholesterolemia, diabetes mellitus, and current smoking, for example, are risk factors associated with dementia and are simultaneous risk factors for cerebrovascular disease. Presence of 3 or more vascular risk factor poses a three-fold risk of developing dementia.3 There is substantial overlap between putative Alzheimer’s risk and established predictors of heart disease and stroke.
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Depressive disorders have been associated with increased risk of development of both Alzheimer’s disease and cognitive decline.2 Depression is associated with incident myocardial infarction and subsequent cardiovascular mortality in late life, as well.7 Late-life depression, as opposed to depression with onset at an earlier age, is associated with higher rates of dementia. Nonetheless, the link between depression and development of dementia is unclear, and further studies need to be performed to decipher the cause and effect roles of the underlying pathology of both depression and dementia.8 Current evidence supports an improvement, but not complete remission, of cognitive symptoms with treatment of geriatric depression. With depressive symptoms affecting over 15% of older Americans,8 clarifying the relationship of screening and treatment of late-life depression and its role in prevention of dementia would be a valuable determination.
Post-mortem research has shown that brain pathology occurs years earlier than the clinical symptoms of dementia. The concept of cognitive reserve may account for the discordance in amount of pathology and the expression of that pathology in the form of cognitive decline.9 Cognitive engagement, leisure activity, and social interactions have been implicated in increasing the amount of reserve, thus slowing the onset of dementia symptoms. Educational level and occupational level have unclear correlations with dementia risk, but recent studies10 have shown that lower levels of literacy lead to a more rapid decline in memory, suggesting that literacy level, an indicator of quality of education, is a better predictor of cognitive decline than level of education.
Disclosure: Dr. Kennedy reports no affiliations with, or financial interests in, any organization that may pose a conflict of interest.
References:
1. Peterson RC. Alzheimer’s disease: early diagnosis. Paper presented at: the NIH-State-of-the-Science Conference on Preventing Alzheimer’s Disease and Cognitive Decline. April 26, 2010; Bethesda, MD.
2. Williams JW, Plassman BL, Burke J, Holsinger T, Benjamin S. Evidence-based practice center presentation I: systematic review methods and the factors associated with the reduction of risk of Alzheimer’s disease and cognitive decline. Paper presented at: the NIH-State-of-the-Science Conference on Preventing Alzheimer’s Disease and Cognitive Decline. April 26, 2010; Bethesda, MD.
3. DeCarli CS. Risk reduction factors for Alzheimer’s disease and cognitive decline in older adults: vascular factors. Paper presented at: the NIH-State-of-the-Science Conference on Preventing Alzheimer’s Disease and Cognitive Decline. April 26, 2010; Bethesda, MD.
4. Torpy JM, Burke AE, Glass RM. Coronary heart disease risk factors. JAMA. 2009;302(21):2388.
5. Framingham Heart Study. Risk Score Profiles. Available at: www.framinghamheartstudy.org/risk/index.html. Accessed June 2, 2010.
6. Bennet DA. Factors that protect against Alzheimer’s disease and cognitive decline. Paper presented at: the NIH-State-of-the-Science Conference on Preventing Alzheimer’s Disease and Cognitive Decline.
7. Arroyo AA, Haan M, Tangen CM, et al, for the Cardiovascular Health Study Collaborative Research Group. Depressive symptoms and risks of coronary heart disease and mortality in elderly Americans. Circulation. 2000;102:1773-1779.
8. Lyketsos CG, Marano C, Norton M, et al. Risk Reduction factors for Alzheimer’s disease and cognitive decline in older adults: depression and related neuropsychiatric disturbances Paper presented at: the NIH-State-of-the-Science Conference on Preventing Alzheimer’s Disease and Cognitive Decline. April 26, 2010; Bethesda, MD.
9. Stern Y. Risk reduction factors for Alzheimer’s disease and cognitive decline in older adults: cognitive engagement. Paper presented at: the NIH-State-of-the-Science Conference on Preventing Alzheimer’s Disease and Cognitive Decline. April 26, 2010; Bethesda, MD.
10. Manly JJ. Risk reduction factors for Alzheimer’s disease and cognitive decline in older adults: sociocultural and demographic. Paper presented at: the NIH-State-of-the-Science Conference on Preventing Alzheimer’s Disease and Cognitive Decline. April 26, 2010; Bethesda, MD.