In the August 10th edition of JAMA is a study about the relationship of obstructive sleep apnea (OSA) and dementia. Researchers believe that memory can be impaired by untreated OSA, but it's not clear if memory is affected by broken up sleep and/or oxygen level dips as a result of the OSA.
Researchers studied 298 women (average age ~82 years old) without dementia at the start of the study. All of them had a sleep study at the beginning of the study. Interestingly, 105 of them had OSA that was at least moderate in severity. The researchers than tested the women for dementia 5 years after their sleep study.
After adjusting for other variables, the results showed that 31% of the women without OSA and that 45% of the women with OSA developed some form of dementia 5 years after their sleep study. Also, the memory defects were associated with oxygen level dips rather than broken up sleep.
One question raised is if treating the OSA will reduce the risk of getting dementia. Also, will this finding extend to men? More studies are needed to answer those questions.