- In a large Canadian study, around 1 in 4 adults aged 45 to 85 were classed as high risk for obstructive sleep apnoea
- People at high risk had higher odds of meeting a combined measure of poorer mental health at the start of the study and again at follow up
- Among those without the combined mental health measure at the start, high risk sleep apnoea was linked with higher odds of meeting it later on
Researchers from Ottawa Hospital Research Institute and the University of Ottawa analysed data from the Canadian Longitudinal Study on Aging.
They wanted to see whether being at high risk of obstructive sleep apnoea was linked with mental health problems at the same time, and whether it was linked with mental health problems developing later.
More than 30,000 adults aged 45 to 85 took part at baseline. Just under 28,000 had follow up data, collected after a median of about three years.
How sleep apnoea risk was identified
Instead of using sleep lab testing, the researchers used a questionnaire score.
People were classed as high risk if they scored 2 or more based on factors such as snoring, daytime sleepiness, someone witnessing pauses in breathing during sleep, or having high blood pressure.
Obstructive sleep apnoea involves repeated narrowing of the upper airway during sleep.
This can interrupt sleep, trigger stress responses in the nervous system, and cause repeated dips in blood oxygen levels.
What counted as poorer mental health
The study used a combined definition so that someone could meet the threshold in more than one way. The composite measure included any of the following:
- A depression symptom score above a set cut off
- A psychological distress score above a set cut off
- A self reported, doctor diagnosed mental health condition
- Self reported antidepressant use
This approach was designed to capture a broad picture rather than rely on one diagnosis alone.
What the study found
High risk sleep apnoea was common.
About 23.5% of participants were classed as high risk at baseline, rising to 27.0% at follow up.
Using the study’s combined mental health measure, about 34.3% met the threshold at baseline and 31.9% at follow up.
After adjusting for other factors that might influence both sleep apnoea risk and mental health, high risk sleep apnoea was associated with higher odds of meeting the combined poorer mental health measure at baseline and at follow up.
Among people who did not meet the combined measure at baseline, high risk sleep apnoea was also linked with higher odds of meeting it by follow up.
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Secondary analyses, including those using witnessed apnoea during sleep and specific mental health diagnoses, showed a similar overall pattern.
Why the link might exist
The researchers pointed to several possible pathways that could help explain the association, including disrupted sleep, repeated low oxygen episodes and inflammation.
They also noted that sleep apnoea often sits alongside cardiometabolic conditions, which can add to physical strain and psychological distress.
The authors suggested that when older adults show signs that point towards sleep apnoea risk, it may be sensible for services to include routine checks for depression and anxiety as part of care.
