Study probes sleep apnoea link to dementia risk

Monash University researchers say a study has reinforced the importance of considering sleep apnoea when looking at future dementia risk.
 
Their work, published this month in the Alzheimer’s & Dementia journal, looked at 2795 cognitively unimpaired Australian residents aged from 40–70, and the impact of obstructive sleep apnoea (OSA) on thinking skills and dementia risk factors.
 
Of the participants, who had all enrolled with the Healthy Brain Project – an initiative exploring what makes people more or less likely to develop dementia – around 7% self-reported an OSA diagnosis.
 
Researchers also carried out online memory tests, and compiled a dementia risk score.
 
They found those with sleep apnoea performed slightly worse on memory tests than those without.
 
They also found those with OSA had a substantially higher dementia risk score but did not directly attribute that to OSA as those participants were also more likely to have risk factors such as obesity, hypertension and high cholesterol.
 
The authors also concluded that OSA may be linked with worse memory and greater dementia risk, regardless of whether participants carried the apolipoprotein E (APOE) ε4 allele, which is described as ‘the strongest known genetic risk factor’ for sporadic Alzheimer’s disease.
 
‘Although these findings should be interpreted cautiously given the cross-sectional design and reliance on self-reported binary treatment status, they are consistent with the possibility that effective OSA management may attenuate the impact of OSA on memory, even in the presence of elevated vascular risk,’ they wrote.
 
For first author Gabriel Abdelmessih, a Monash University Clinical Neuropsychology PhD candidate, the findings also point to the value of early OSA screening to identify people at greater risk of dementia.
 
‘Sleep apnoea is common, frequently undiagnosed, and highly treatable, yet it is not often considered in discussions about dementia risk,’ he said. 
 
‘Our findings suggest that identifying and managing sleep apnoea in midlife may represent an important opportunity to support long-term brain health.’
 
The authors said future randomised controlled trials are ‘needed to investigate whether targeting OSA together with associated vascular comorbidities could potentially slow or prevent cognitive decline or reduce dementia risk in later life’.
 
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