SYDNEY, Dec. 14 (Xinhua) -- People with irregular sleep patterns could have an increased risk of dementia compared to those who wake and sleep at more regular times, a research led by Australia's Monash University showed on Thursday.
The study didn't prove that irregular sleep causes dementia, but showed an association, the Melbourne-based university said in a media release.
The community-based prospective cohort study examined the relationship between sleep regularity and the risk of getting dementia in the future.
The research, which was published in Neurology, the official journal of the American Academy of Neurology, also looked at brain volume on brain scans.
Researchers used sleep regularity data for 88,094 UK Biobank participants whose average age was 62. The sleep regularity index was measured using a wrist device. Over a mean of 7.2 years follow-up, 480 participants developed dementia.
Those who had the most irregular sleep patterns had the highest dementia risk, according to the study.
Senior author Associate Professor Matthew Pase, of Monash University's School of Psychological Sciences and Turner Institute for Brain and Mental Health, said the results underlined the importance of regular sleep patterns.
"Irregular sleep patterns may disrupt our internal biological clock, which controls our 24-hour circadian rhythms," Pase said. "Many of our body's processes, including metabolism of our blood sugars and fats and control of blood pressure follow a 24hr diurnal (day/night) rhythm."
"Disruption to these rhythms may increase risk of hypertension, diabetes, high cholesterol and obesity. Combined, these factors are linked to damage of blood vessels and inflammation in the brain, possibly leading to neurodegeneration and subsequent dementia," he said.
First author Dr. Stephanie Yiallourou, of Monash University's School of Psychological Sciences and Turner Institute for Brain and Mental Health, said more emphasis needed to be placed on regular sleep and health.
"I think many people are probably unaware of the links," Yiallourou said. "This is because most of our sleep research, to date, has focused on investigating sleep durations and associated health outcomes, rather than how regular our sleep is." ■