April 4, 2014 | Robert Preidt
It included more than 2,800 men, average age 76, in six locations across the United States. Sleep data was collected from the men through a wrist device for an average of five nights, and participants underwent tests to assess their attention and executive function.
Executive function includes planning, making decisions, correcting errors, troubleshooting and abstract thinking.
The researchers found that higher levels of poor sleep quality were associated with a 40 percent to 50 percent increased risk of significant decrease in executive function, similar in degree to the effect of a five-year increase in age. Length of sleep did not affect the men's mental skills, according to the study published in the April issue of Sleep.
"It was the quality of sleep that predicted future cognitive decline in this study, not the quantity," lead author Terri Blackwell, senior statistician at the California Pacific Medical Center Research Institute in San Francisco, said in a journal news release.
"With the rate of [mental] impairment increasing and the high prevalence of sleep problems in the elderly, it is important to determine prospective associations with sleep and cognitive decline," Blackwell added.
The study did not find a cause-and-effect relationship between poor sleep and mental decline in older men, just an association.
The mechanisms that link poor sleep to mental decline aren't known, and further research is needed to determine if this association remains after a longer follow-up period, the study authors said.
The U.S. National Heart, Lung, and Blood Institute provided study funding.