Obstructive sleep apnoea syndrome and future risk of dementia among individuals managed in UK general practice

Background: Obstructive sleep apnoea syndrome (OSAS) has been recognised as a potential risk factor for cognitive decline, yet its precise relationship with dementia remains uncertain. This study aimed to determine the risk of dementia among individuals with and without OSAS.

Methods: Data derived from 2.3 million adults (aged ≥18 years) were extracted from the Clinical Practice Research Datalink (2000-2022), a nationally representative primary care electronic health records database in the UK. 193 600 individuals with OSAS were propensity score-matched to 536 701 individuals without OSAS. Cox proportional hazard regression models were applied to quantify the risk of developing all-cause dementia, vascular dementia and Alzheimer's disease between individuals with and without OSAS.

Results: With a median follow-up of 4.0 (IQR 1.8-7.5) years, 2802 and 6211 individuals developed all-cause dementia in those with and without OSAS, corresponding to crude incidence rates of 2.47 and 2.34 per 1000 person-years, respectively. The presence of OSAS was associated with higher risks of all-cause dementia (adjusted HR (aHR) 1.12, 95% CI 1.07 to 1.17), vascular dementia (1.29, 95% CI 1.19 to 1.41) and unchanged risk of Alzheimer's disease (1.07, 95% CI 0.99 to 1.16). Individuals with OSAS who had received continuous positive airway pressure (CPAP) treatment exhibited a similar risk of all-cause dementia as their matched counterparts (0.99, 95% CI 0.74 to 1.32).

Conclusion: OSAS is associated with higher risks of all-cause dementia and some of its subtypes. Further investigation is needed to investigate the clinical benefits of screening for cognitive impairment in people with OSAS and to further evaluate the impact of CPAP on cognitive decline and dementia risk.