Untreated sleep apnoea may be risk factor for dementia

People who have obstructive sleep apnoea may have an increased risk of dementia if left untreated, according to a new study of UK electronic healthcare records.

The study published in BMJ Thorax reviewed 2.3 million healthcare records across 12 years in the UK, and found that among the 193,000 individuals with obstructive sleep apnoea syndrome (OSAS) there was a 12% higher risk of developing all-cause dementia and a specific 29% increased risk of developing vascular dementia, although the risk of developing Alzheimer’s Disease was unchanged.

However, patients who received a treatment called Continuous Positive Airway Pressure (CPAP) to help regulate breathing during sleep did not see a raised risk compared to the general public. Furthermore, female patients with sleep apnoea also didn’t have a higher risk.

Dr Jingya Wang from the University of Birmingham and corresponding author of the study said:

“Our findings build on existing evidence that sleep apnoea is associated with issues of cognitive decline, and we can see that when left untreated, OSAS can increase the risk of developing vascular dementia in particular.

“Using a large electronic healthcare dataset also meant we are able to see that women aren’t at risk in the same way that men are, which also corresponds with other studies that there are different factors that affect men and women developing dementia.”

The study used a data tool called DExTER to find relevant healthcare records of patients with sleep apnoea for use in the study, as well as up to four suitable individuals to act as a control group.

The resulting dataset of 193,600 of patients with OSAS was compared to more than half a million patients without OSAS, and an average of a four-year period was reviewed to find patients who had been diagnosed with a type of dementia.

Analysis of the dataset found that OSAS patients, regardless of age and body mass index had an increased risk of developing all-cause and particularly vascular dementia.

Dr Shamil Haroon from the University of Birmingham and the senior author of the study said:

“This study provides further evidence that some conditions such as sleep apnoea could contribute to an additional risk of developing diseases such as dementia. It also backs up other findings that may suggest that the periods of hypoxia, where there are lower levels of oxygen in the body, may be contributing to vascular dementia risk. Clinicians should consider these risks when supporting their patients with obstructive sleep apnoea.”