This article is more than 5 years old. Information may no longer be current.

Longer sleep duration may cause cognitive decline in Hispanic, Latino adults

Among Hispanic and Latino adults in the United States, long sleep duration predicted 7-year neurocognitive decline, according to study results published in Alzheimer’s & Dementia. The researchers noted that longer habitual sleep duration may either be a warning sign of or a risk factor for this decline.

“Insomnia and prolonged sleep duration appear to be linked to a decline in neurocognitive function that can precede the onset of Alzheimer’s disease or other dementias,” Alberto R. Ramos, MD, MSPH, associate professor of neurology at the University of Miami, said in a news release. “This finding is particularly important because Hispanics have a significantly higher risk of Alzheimer’s disease compared with non-Hispanic whites.”

The risk for Alzheimer's disease and related dementias, according to the researchers, is four times that of non-Hispanic whites, but there is currently limited research on sleep disturbances and associations with neurocognitive decline in this minority group, they wrote. Ramos and colleagues conducted their study to determine if several factors — sleep-disordered breathing, daytime sleepiness, insomnia and sleep duration — predicted 7-year neurocognitive decline among a cohort of 5,247 U.S. Hispanics/Latinos aged 45 to 75 years. The mean age was 63 years, and 55% of the population were female, 7% were Central American, 24.5% were Cuban, 9.3% were Dominican, 35.9% were Mexican, 14.4% were Puerto Rican and 5.1% were South American.

At the start of the study, the researchers administered a neurocognitive test to the patients, and then repeated the test 7 years later. They used episodic learning and memory, word fluency, processing speed and a cognitive impairment screener as outcomes.

They found that sleep duration of 9 hours or more was associated with decline in episodic learning and memory, word fluency and cognitive impairment screener scores but not processing speed. Short sleep duration of 6 hours or less, sleepiness and insomnia were not associated with neurocognitive decline.

“Longer habitual sleep duration could be an early marker of dementia with possible sleep cycle changes or increased sleep need manifested as longer bedtimes,” the researchers wrote. “Proper sleep may facilitate beta amyloid clearance from the brain; however, this remains undefined in long sleepers.” – by Joe Gramigna

Disclosures: The authors report no relevant financial disclosures.