Sleep disturbances among Hispanics may increase their risk of cognitive impairment and Alzheimer’s disease, according to a new study led by a University of Miami Miller School of Medicine neurologist and sleep expert.
“Insomnia and prolonged sleep duration appear to be linked to a decline in neurocognitive functioning that can precede the onset of Alzheimer’s disease or other dementias,” said Alberto R. Ramos, M.D., MSPH, associate professor of neurology. “This finding is particularly important because Hispanics have a significantly higher risk of Alzheimer’s disease compared with non-Hispanic whites.”
Dr. Ramos was the lead author of the collaborative study, “Sleep and Neurocognitive Decline in the Hispanic Community Health Study / Study of Latinos” published October 9 in Alzheimer's & Dementia: The Journal of the Alzheimer's Association. The multi-center research team analyzed participants in the nationwide Hispanic Community Health Study/Study of Latinos, which includes about 16,000 Latinos from diverse backgrounds at four major urban centers in Chicago, Miami, San Diego and the Bronx in New York City.
“We followed 5,247 participants between 45 and 75 years old, giving them a neurocognitive test at the start and repeating the test seven years later,” said Dr. Ramos, who is research director of the Miller School’s sleep disorders program. His team’s research is aimed at the intersection between sleep disorders, cerebrovascular disease and neurocognitive aging in population-based studies.
“We observed that prolonged periods of sleep and chronic insomnia symptoms led to declines in memory, executive function and processing speed. Those measures can precede the development of mild cognitive impairment and Alzheimer’s disease.”
Funded by the National Institutes of Health, the groundbreaking epidemiological study also included measures of sleep apnea, which has been linked to impaired cognition. “No previous studies used data from a representative sample of U.S. Hispanic/Latinos for these multiple types of sleep disturbances,” said Dr. Ramos.
Dr. Ramos said the findings provide a foundation for building awareness among physicians that sleep disturbances may be linked to neurocognitive decline, particularly in Hispanic patients. “We may also be able to identify at-risk patients who may benefit from early intervention to prevent or reduce the risk of dementia,” he said.
Future research may involve quantifying the potential synergistic effect of sleep disorders with cerebrovascular disease as a pathway to neurocognitive decline. Dr. Ramos added, “We may also want to look at an individual’s circadian rhythms or internal clocks, as well as genetic studies that can clarify the relationships of sleep disorders with neurocognitive decline.”