Data obtained from 14 previously published studies with a total of
more than 4.2 million men and women showed that people with
sleep-disordered breathing had 26 percent higher odds of developing
cognitive impairment, researchers report in JAMA Neurology.
“Identification of this sleep disorder in elderly persons might help
predict future risk of cognitive impairment and thus is important
for the early detection of dementia,” said lead study author Yue
Leng of the University of California, San Francisco.
“Moreover, sleep-disordered breathing is a treatable disease,” Leng
said by email. “If sleep-disordered breathing is a risk factor for
dementia, then treatment of sleep-disordered breathing might benefit
cognition and help reduce the risk of dementia in the long run.”
Many people with nighttime breathing problems had what’s known as
apnea, a potentially serious sleep disorder that involves repeated
stops and starts in breathing. Risk factors for sleep apnea include
older age and obesity.
In the smaller studies included in the analysis, the increased risk
of cognitive impairment associated with sleep-disordered breathing
ranged from 23 percent to 86 percent.
When researchers analyzed the increased risk across all of the
smaller studies with a similar design, excluding one that was done
much differently, the overall increased risk of cognitive impairment
associated with sleep-disordered breathing was 35 percent.
Sleep-disordered breathing was also associated with slightly worse
“executive function” – that is, the mental processes involved in
planning, paying attention, following instructions, and
multi-tasking, for example - but it didn’t appear to influence
memory, the study also found.
The researchers had only limited data on executive function,
however, which made it difficult to determine whether any changes
associated with sleep-disordered breathing might be clinically
The analysis also didn’t account for obesity, which is independently
a risk factor for both apnea and cognitive impairment, noted
Marie-Pierre St-Onge, a researcher at Columbia University Medical
Center in New York City who wasn’t involved in the study.
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“It’s possible that the reduction in oxygen reaching the brain from
apnea could, over time, lead to brain injuries that can lead to
cognitive impairment,” St-Onge said by email. “There is also a link
between obesity and mild cognitive impairment and between obesity
and sleep-disordered breathing.”
Shedding excess weight might help, said Hui-Xin Wang of the
Karolinska Institute in Stockholm.
“Weight-loss strategies, including physical exercise and diet, have
been evaluated as a treatment strategy to improve sleep-disordered
breathing and reduce the risk of cognitive decline,” Wang, who
wasn’t involved in the study, said by email.
Beyond weight loss, treatments for apnea may include wearing a
breathing mask or jaw support at night to keep airways open.
More research is needed, however, to determine whether and to what
extent treating sleep apnea might lower the risk of cognitive
decline, said Kristen Knutson of the Center for Circadian and Sleep
Medicine at the Northwestern University Feinberg School of Medicine
“There are therapies available for apnea that would improve sleep
and potentially improve health, including cognitive function,”
Knutson, who wasn’t involved in the study, said by email. “People
who have trouble sleeping or who snore loudly and frequently should
raise this issue with their doctors and discuss potential
SOURCE: http://bit.ly/2wM2z1v JAMA Neurology, online August 28,
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