Researchers identify sleep habits that substantially increase dementia risk

[Oct 2, 2022: Staff Writer, The Brighter Side of News]


How long people sleep and when they go to bed could influence their risk of dementia. (CREDIT: Creative Commons)


According to a new study, how long people sleep and when they go to bed could influence their risk of dementia.


The results were published in the Journal of the American Geriatrics Society.


Researchers from China, Sweden, and the United Kingdom found that sleep for more than eight hours increased dementia risk by 69%, while sleeping before 9 p.m. rather than 10 p.m. or later, increased dementia risk by two times.


 
 

Furthermore, the study found that "cognitive function should be monitored in older adults who report prolonged time in bed and advanced sleep timing, especially in older males aged 60 to 74."


Research in the future "may clarify whether moderately reducing [time in bed] and delaying sleep timing can help slow down cognitive decline and delay dementia onset in older adults," wrote Dr. Rui Liu, the lead author of the study, from Shandong University's Shandong Provincial Hospital in Jinan, China.


 

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A total of 97 participants were diagnosed with dementia during an average follow-up period of 3.7 years out of 2,000 older adults in China who were free of dementia at the beginning of the study.


The researchers noted that the majority of studies on sleep and dementia have focused almost exclusively on White populations in North America and Europe.


 
 

The study noted that older Chinese citizens living in rural areas tend to go to bed earlier, wake up earlier, sleep less, and be more likely to develop dementia compared to Westerners and city dwellers, partly due to differences in socioeconomic status, culture, education, and lifestyle.


Multivariable-adjusted spline curves for associations of sleep characteristics with incident dementia (n = 1982). Solid lines represented hazard ratios of incident dementia, adjusting for age, sex, education, body mass index, alcohol consumption, smoking, hypertension, diabetes, dyslipidemia, coronary heart disease, stroke, and APOE genotype. The shaded areas represented the 95%CI. The histogram represented the distribution of study participants. CI, confidence interval. (CREDIT: Associations of sleep timing and time in bed with dementia and cognitive decline among Chinese older adults: A cohort study)


To try to bridge the knowledge gap, study participants were rural-dwelling, older adults, mostly low-income and with limited education, in western Shandong Province.


 
 

Scientists noted that sleep problems and cognitive decline are related to demographics, such as age, sex, and education. In addition, short sleep duration is well-established as a genetic risk factor for dementia.


Associations of baseline sleep characteristics with MMSE score changes among participants who were free of dementia at follow-up, stratified by baseline age groups (60–74 vs. ≥75 years) and sex (n = 1845). Results were adjusted for age, sex, education, body mass index, alcohol consumption, smoking, hypertension, diabetes, dyslipidemia, coronary heart disease, stroke, APOE genotype, baseline MMSE score, and follow-up time. (CREDIT: Associations of sleep timing and time in bed with dementia and cognitive decline among Chinese older adults: A cohort study)


The link between sleep problems and dementia has, however, been found to be inconsistent in population-based studies, the researchers said.


 
 

According to the authors, the results should be interpreted with caution, due to the fact that sleep characteristics were self-reported, there were no data on factors such as sleep apnea, and there was a relatively short period of follow-up monitoring.




For more science news stories check out our New Discoveries section at The Brighter Side of News.


 

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