Scientists already think that regular poor sleep, especially during middle age, could increase your chances of developing dementia (less than five hours a night is associated with double the risk).
And a sudden change in how long you sleep may be related to a condition years before diagnosis.
We ‘re not exactly sure how or why sleep might have this effect on the brain. But a recent paper has added to the existing associations.
Researchers involved in the study found that those with “chronic insomnia” could face an increased risk of dementia.
How much poor sleep does it take to increase my risk of dementia?
In this article, “chronic insomnia” was defined as difficulty sleeping at least three nights a week for at least three months.
About 2,750 participants with an average age of 70 were followed for 5.6 years. All of them were free of dementia at the start of the study, and 16% had chronic insomnia.
After conducting memory and thinking tests, as well as brain scans, scientists found that those who reported a sleep-disordered sleep pattern had more amyloid plaque formation, which is linked to the development of dementia.
Of those who self-reported chronic insomnia at the start of the study, 14% went on to develop insomnia, compared to 10% among those who had no sleep problems.
People with insomnia were 40% more likely to develop mild cognitive impairment or dementia than those without insomnia.
Speaking to MedicalNewstoday, lead author of the study, Dr Diego Z Carvalho, said: “In our models, the impact of insomnia on the risk of mild cognitive impairment/dementia was greater than two cardiometabolic conditions, such as hypertension and diabetes, or being 3.5 years older than your actual age, which are known risk factors.”
Why might insomnia affect dementia risk?
We still can’t say for sure, but Dr. Carvalho suggested this study has given him some ideas.
“We found that insomnia with reduced sleep was associated not only with biomarkers of Alzheimer’s disease, such as amyloid, but also with poorer cerebrovascular health with greater evidence of small vessel disease, as shown by white matter hyperintensity,” he said.
This is important because both amyloid plaque protein buildup and poorer cardiovascular health are independently associated with increased risk of dementia.
The lead researcher also recommended that more doctors include sleep tests in their routine screening, especially with older patients.
