Study shows Hispanics/Latinos at greater risk of long-term cognitive decline from poor sleep
Poor sleep impacts the risk of long-term cognitive decline in Hispanic/Latino middle-aged and older adults differently than it does in non-Hispanic/Latino adults. This information comes from research led by the University of Miami (Florida) Miller School of Medicine neurology faculty and the largest long-term study of U.S. Hispanics/Latinos to date.1
During the seven years of follow-up, Hispanics/Latinos were more likely to develop cognitive declines in processing speed, mental flexibility, and verbal memory, if they had sleep-disordered breathing, such as obstructive sleep apnea, and long sleep duration of nine or more hours. The risk was especially high in middle-aged adults without metabolic syndrome and women without obesity or metabolic syndrome, according to the paper recently published in Alzheimer’s & Dementia, the Journal of the Alzheimer’s Association.2
Why is this true? Sonya Kaur, Ph.D, instructor in the Division of Neuropsychology at the Miller School said, “The work shows that the metabolic risk factors that predict neurocognitive decline in non-Hispanics/Latinos are not generalizable to Hispanics/Latinos.” Dr. Kaur continued, “In general, the relationship between sleep and cognition was not mediated by metabolic syndrome and obesity in Hispanics like it is in non-Hispanics. For Hispanics, sleep seems to be a much stronger predictor than obesity and metabolic syndrome that are traditionally thought of as predictors in terms of what causes cognitive decline in non-Hispanics.”2
This is especially important because, compared to non-Hispanic whites, Hispanics/Latinos are at a greater risk for metabolic syndrome, and are at four times the risk of Alzheimer’s Disease and related dementias, according to Dr. Kaur.2
Being at greater risk raises a question about how common or rare screenings for sleep apnea are in the Hispanic/Latino population. An earlier study with this same group found that “sleep-disordered breathing is prevalent in U.S. Latinos but rarely associated with a clinical diagnosis. Only 1.3% of participants reported a sleep apnea diagnosis.”4 This suggests a critical need for testing along with screening, whether in-laboratory polysomnography or home sleep apnea tests (HSATs).
Alberto Ramos, M.D., M.S.P.H., Study Senior Author, Associate Professor of Neurology, and Research Director of Sleep Disorders program, University of Miami Miller School of Medicine:
“In the big picture, these findings have implications for how we can personalize treatment of sleep disorders to more effectively lessen cognitive decline, prevent neurocognitive disorders such as Alzheimer’s disease and preserve brain health.”2
Ramos continued, “A surprising finding of this study of 5,500 U.S. Hispanic/Latino adults was that participants without obesity that had sleep apnea and long sleep duration had worse cognitive decline. To some extent, this was like a natural experiment where we removed the effect that obesity has on cognition and saw ‘the pure effect’ of sleep difficulties, such as sleep apnea, and long sleep duration on cognitive health.”2
The Miller School has long been a leader in identifying disorders and risk factors associated with dementia and Alzheimer’s and Hispanic health. Dr. Ramos is also an investigator of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), where he serves as primary consultant for Sleep Research at the Miami site. Dr. Ramos is supported by NIH/NIA to evaluate sleep phenotypes, neurocognitive decline, and incident dementia in HCHS/SOL.2,3
Previously, Dr. Ramos and his colleagues published data showing a high prevalence of sleep disorders associated with neurocognitive dysfunction, including memory decline, in a diverse population of Hispanic/Latino participants.2
Dr. Kaur concluded by saying, “We are conducting ongoing research on the cognitive effects of migration factors and genetic risk factors in Hispanic patients, because there is evidence that genetic risk factors in non-Hispanic whites do not predict cognition decline in the same way as in Hispanics.”2
Kaur, S. S., et al. (2021) Modifying pathways by age and sex for the association between combined sleep disordered breathing and long sleep duration with neurocognitive decline in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Alzheimer’s & Dementia. doi.org/10.1002/alz.12361.
Henderson, E. Poor sleep increases risk of long-term cognitive decline in Hispanics/Latinos. News Medical Life Sciences. May 28, 2021. https://www.news-medical.net/news/20210528/Poor-sleep-increases-risk-of-long-term-cognitive-decline-in-HispanicsLatinos.aspx
University of Miami Miller School of Medicine, Evelyn F. McKnight Brain Institute, Albert Ramos biographical entry. mbi-umiami.org
Sleep-disordered breathing in Hispanic/Latino individuals of diverse backgrounds. The Hispanic Community Health Study/Study of Latinos.Redline S, Sotres-Alvarez D, Loredo J, Hall M, Patel SR, Ramos A, Shah N, Ries A, Arens R, Barnhart J, Youngblood M, Zee P, Daviglus ML.Am J Respir Crit Care Med. 2014 Feb 1;189(3):335-44. doi: 10.1164/rccm.201309-1735OC.PMID: 24392863