Dementia: Early bedtime, sleeping over 8 hours may increase risk - Medical News Today

At least 6% of older adults, or one in 20 people age 60 or over, live with dementia.

A recent population-based study of older people in rural China linked prolonged sleep and early sleep timing with an increased risk of dementia.

The study also found that even in those who did not develop dementia during the study time, there was still a degree of cognitive decline associated with prolonged sleep and early bedtimes.

Older adults in rural China typically go to sleep earlier, rise earlier, and have lower quality sleep than their white counterparts or people in urban areas.

The present study’s aim was to “examine the associations of self-reported sleep characteristics (e.g., TIB, sleep timing, sleep duration, sleep quality, and EDS) with incident dementia, Alzheimer’s disease (AD), and cognitive decline, while taking into account their potential interactions with demographic features and APOE genotype.”.

The current cohort study recruited participants in the Shandong Yanggu Study of Aging and Dementia, which involved rural older people in western Shandong province.

Among those who did not develop dementia during the study, baseline long TIB, early bedtime and mid-sleep time, and early and late rise time metrics were “significantly associated” with a greater reduction in cognitive decline as evidenced by MMSE scores.

Further, whilst the dementia results were the same in different demographic groups, the cognitive decline changes in those free from dementia were evident only among individuals ages 60–74 years, but not among subjects ages 75 years and older.

Porter offered possible reasons for the higher risk of cognitive decline in men:.

Neither did the study consider mood-related symptoms or daytime napping, which is common among older adults in rural China.

They say that their results should encourage monitoring of older adults “who report prolonged TIB and advanced sleep timing, especially in older individuals [ages] 60–74 years and men.”

Future work may explore how reducing TIB and adjusting sleep timing might hold back the onset of cognitive decline and dementia

A study found that the risk of older people developing Alzheimer's disease over a one-year period nearly doubled following a COVID-19 diagnosis