A recent study has uncovered an association between women who suffer from sleep apnea and the likelihood of developing dementia. Oxygen intake levels could be the culprit as a lack of the element may stunt long term memory. Among the women found to suffer from sleep disordered breathing, 44.8% of them developed dementia or mild cognitive impairment, compared with 31.1% of those who didn’t have impaired breathing and sleep.
Kristine Yaffe, MD, professor of psychiatry, neurology and epidemiology at UCSF and chief of geriatric psychiatry at SFVAMC stated:
“This is the first study to show that sleep apnea may lead to cognitive impairment. It suggests that there is a biological connection between sleep and cognition and also suggests that treatment of sleep apnea might help prevent or delay the onset of dementia in older adults. While we cannot conclude from these results that SDB causes cognitive impairment, our study suggests that it may at least be a contributing factor.”
In people with sleep apnea, the airways leading from the lungs to the nose and mouth collapse as the individuals sleep, interfering with the ability to inhale. People with sleep apnea usually snore, sometimes loudly, and are wakened many times a night for tiny fragments of time as they gasp for air.
The strength of the new findings comes from the fact that the 298 subjects began the study without dementia or measurable cognitive impairments, allowing researchers to measure the relationship between sleep apnea and mental acuity. These women, drawn from a larger, ongoing study examining osteoporosis in more than 10,000 women over 65, were first examined at clinics in Pittsburgh and Minneapolis and given tests that assessed their mental and cognitive abilities. Those who were found to be suffering from dementia or mild cognitive impairment at the initial assessment weren’t included in the study.
After four years had passed, sleep specialists came to the study subjects’ homes and monitored the women as they slept using specialized equipment that measured brain activity, heart rhythm, leg movements, airflow, breathing activity in their chest and abdomen and the oxygen content of blood as it passed through their fingers.
Then after about five more years, the women returned to the clinics and were given a larger battery of tests that measured their cognitive abilities, memory and verbal fluency. Women whose test results suggested they had dementia or mild cognitive impairment had their records reviewed by a panel of clinical experts who decided whether to confirm the diagnosis.
When Yaffe and her colleagues tabulated the results of the study, they found that about one third (35.2 percent) of all the women developed dementia or mild cognitive impairment. They also found that those with sleep apnea were almost twice as likely to become cognitively impaired.
Women who had frequent episodes of low oxygen or spent a large portion of their sleep time in a state of hypoxia were more likely to develop cognitive impairment. The new findings suggest that providing oxygen therapy to elderly people with sleep apnea may reduce the chances of them becoming cognitively impaired or delay the onset of mental decline.
Written by Sy Kraft