This study analyzed existing data from a long-term study of 8,000 Britons conducted by University College London since 1985.As part of the research project, participants report How long did they sleep Many times in 25 years. Some of them also wear sleep tracking devices to ensure that they give accurate numbers of their sleep time.
Then, a team of researchers looked for any correlation between insufficient sleep and a greater risk of dementia.
Researchers have long suspected a link between sleep and the risk of dementia, but they have not been sure where the link started. In other words, we don’t know whether lack of sleep makes people vulnerable to dementia, or whether dementia makes people lose sleep.
The important thing about this study is that it started to follow the sleep patterns of people in their 50s, presumably before the onset of dementia.