OSA Is Linked to Alzheimer Risk
Obstructive sleep apnea (OSA) may be associated with the risk for Alzheimer disease (AD), according to a recent study.1
Approximately 5 million people in the United States have AD, and 30% to 80% of elderly individuals have OSA. But the association between the two is currently unknown.
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To examine this association, Ricardo S. Osorio, MD, of New York University School of Medicine, and colleagues assessed 208 participants age 55 to 90 years with normal cognition, as determined by standardized tests and clinical evaluations. None of the participants had been referred by a sleep center, had used continuous positive airway pressure (CPAP) for sleep apnea, had been depressed, or had a medical condition that could impact their brain function.
Participants’ cerebrospinal fluid (CSF) soluble amyloid beta (Ab) levels were obtained via lumbar punctures. In a subgroup of participants, positron emission tomography was used to measure Ab deposits directly in the brain.
Results of the study showed that more than half of participants had OSA. Of these participants, 36.5% had mild OSA and 16.8% had moderate to severe OSA. Furthermore, in a subgroup of 104 participants who participated in a 2-year longitudinal study, OSA severity correlated with a decrease in CSF Ab42 levels over time.
However, the researchers noted that OSA severity did not predict cognitive deterioration in this cohort of healthy elderly adults.
Ultimately, the findings of this study suggested that CPAP, dental appliances, positional therapy and other treatments for OSA could potentially delay cognitive impairment and dementia in many older adults.
“Results from this study, and the growing literature suggesting that OSA, cognitive decline and AD are related, may mean that age tips the known consequences of OSA from sleepiness, cardiovascular, and metabolic dysfunction to brain impairment,” said Dr Osorio. “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.”2
—Christina Vogt
References:
1. Sharma RA, Varga AW, Bubu OM, et al. Obstructive sleep apnea severity affects amyloid burden in cognitively normal elderly: a longitudinal study [published online November 10, 2017]. Am J Respir Crit Care Med. http://www.thoracic.org/about/newsroom/press-releases/resources/osa-and-alzheimers.pdf.
2. Sleep apnea may increase risk of developing Alzheimer’s disease [press release]. American Thoracic Society. Accessed on November 10, 2017.