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3 Risk Factors for Cognitive Decline in Older Adults

3 Risk Factors for Cognitive Decline in Older Adults


Elderly patients are prone to sleep apnea, heart disease, and depression. These conditions may affect the risk of Alzheimer disease or the ability to cope with daily activities, according to 3 new studies.1-3

Details of these studies—and their clinical implications—are briefly summarized here.


Study 1. Sleep Apnea Elevates Risk of Alzheimer Disease
Biomarkers for amyloid beta, the plaque-building peptides associated with Alzheimer disease, increase over time in elderly adults with obstructive sleep apnea (OSA).

The study
A 2-year prospective, longitudinal study included 208 participants, age 55 to 90, with normal cognition who were not depressed.1 More than half of the participants had OSA, including 36.5% with mild OSA and 16.8% with moderate to severe OSA.

The severity of OSA correlated with a decrease in cerebrospinal fluid amyloid beta levels over time, which is compatible with an increase in amyloid deposits in the brain. This finding was confirmed in a subset of participants who underwent amyloid PET, which showed an increase in amyloid burden in those with OSA.

Clinical implications
Several studies suggest sleep disturbances might contribute to amyloid deposits and accelerate cognitive decline in those at risk for Alzheimer disease. “Results from this study, and the growing literature suggesting that OSA, cognitive decline, and Alzheimer’s disease are related, may mean that age tips the known consequences of OSA from sleepiness, cardiovascular, and metabolic dysfunction to brain impairment,” said senior author Ricardo S. Osorio, MD, Assistant Professor of Psychiatry at New York University School of Medicine. “If this is the case, then the potential benefit of developing better screening tools to diagnose OSA in the elderly, who are often asymptomatic, is enormous.”



1. Sharma RA, Varga AW, Bubu OM, et al. Obstructive sleep apnea severity affects amyloid burden in cognitively normal elderly: a longitudinal study. Am J Respir Crit Care Med. 2017 Nov 10. doi: 10.1164/rccm.201704-0704OC. [Epub ahead of print]

2. Jefferson AL, Liu D, Gupta DK, et al. Lower cardiac index levels relate to lower cerebral blood flow in older adults. Neurology. 2017 Nov 8. DOI: https://doi.org/10.1212/WNL.0000000000004707. [Epub ahead of print]

3. Nakamura T, Michikawa T, Imamura H, et al. Relationship between depressive symptoms and activity of daily living dependence in older Japanese: The Kurabuchi Study. J Am Geriatr Soc. 2017 Sep 27. doi: 10.1111/jgs.15107. [Epub ahead of print]

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