Poor sleep may speed up brain aging, found a new study published in eBioMedicine. The findings support the idea that poor sleep may be a risk factor for developing dementia.
Previous studies have linked poor sleep with a higher risk for dementia. Until now, however, it has been unclear whether difficulty sleeping contributes to dementia or is a consequence of prodromal stages of the disease. In the current study, researchers investigated the link between healthy sleep patterns and brain aging, as well as the extent to which they are mediated by systemic inflammation.
For the study, the researchers analyzed data from 27,500 adults with an average age of 55 years old from the UK Biobank. Data included five self-reported measures of sleep: chronotype (being a morning or evening person), having 7-8 hours of sleep daily, insomnia, snoring, and daytime sleepiness.
Participants were divided into three groups according to sleep score- 4-5 points indicating ‘healthy’ sleep, 2-3 points: intermediate sleep, and 1 point or less: poor sleep. The researchers also examined measures of low-grade inflammation. Brain aging was estimated using a machine learning model based on 1079 MRI phenotypes after a mean follow-up of 9 years.
Ultimately, the researchers found that the gap between brain age and chronological age increased by around six months for every 1-point decrease in healthy sleep score. On average, people with poor sleep had brain ages around a year older than their actual age, said lead author of the study, Abigail Dove, researcher at the Department of Neurobiology, Care Sciences and Society at Karolinska Institutet, Sweden, in a press release.
The researchers further found that various measures of chronic inflammation- including white blood cell count, platelet count, and C-reactive protein- could explain over 10% of the link between poor sleep and older brain age.
"Our findings provide evidence that poor sleep may contribute to accelerated brain aging and point to inflammation as one of the underlying mechanisms. Since sleep is modifiable, it may be possible to prevent accelerated brain aging and perhaps even cognitive decline through healthier sleep,” said Dove.
Sources: Science Daily, eBioMedicine