Poor sleep may raise risk of dementia
People who sleep poorly, particularly as a result of sleep apnea, may be at a greater risk of developing dementia. That's the conclusion of a new study published in the journal Neurology.
The link is based on results showing that people who have low oxygen levels in the blood are more likely to have brain lesions called microinfarcts, which have been associated with dementia.
The researchers gave sleep tests to 167 men with an average age of 84. The participants were analyzed until they died. The researchers then conducted autopsies on their brains, assessing potential brain cell loss and searching for evidence of microinfarcts and brain abnormalities associated with Alzheimer's disease and Lewy body dementia. The researchers divided the participants into four different groups, based on the amount of time they had spent with lower-than-normal oxygen levels during sleep.
At one end of the groups studied, people spent up about 13 percent of their time sleeping with low oxygen levels, while the highest group spent between 72 to 99 percent of their time sleeping with low oxygen levels. The lowest group had only four men who had microinfarcts in their brains, compared with 14 of the 42 men in the highest group. As a result, men in the highest group were four times more likely to have brain damage than those in the lowest group. The researchers also found that spending less time in deep sleep, also referred to as slow wave sleep, increased the likelihood of losing brain cells.
The researchers aren’t certain about the cause of low oxygen levels in the blood, but sleep apnea is a factor. More tests need to be done to see whether sleep apnea prevention and better short wave sleep could reduce the risk of cognitive decline.