The results of this epidemiological study suggest that suffering from untreated sleep apnea can raise the risk of later dementia and mild cognitive impairment by 20-30%. How the repeated hypoxia in the brain produced by sleep apnea results in a raised risk of dementia isn't understood in detail, but it has been shown to lead to structural changes in brain regions connected to memory. It is also possible that the correlation of obesity with sleep apnea muddies the waters, and that sleep apnea isn't actually the primary issue, given the harms dcaused by excess visceral fat tissue. That makes the data here interesting, in that it compares treated and untreated patients exhibiting sleep apnea, and finds a meaningful difference.
To examine associations between positive airway pressure (PAP) therapy, adherence, and incident diagnoses of Alzheimer's disease (AD), mild cognitive impairment (MCI), and dementia not-otherwise-specified (DNOS) in older adults, this retrospective study utilized Medicare data of 53,321 beneficiaries, aged 65+, with an obstructive sleep apnea (OSA) diagnosis prior to 2011.
Study participants were evaluated using ICD-9 codes for neurocognitive syndromes [AD(n=1,057), DNOS(n=378), and MCI(n=443)] that were newly-identified between 2011-2013. PAP treatment was defined as presence of ≥1 durable medical equipment (HCPCS) code for PAP supplies. PAP adherence was defined as ≥2 HCPCS codes for PAP equipment, separated by ≥1 month. Logistic regression models, adjusted for demographic and health characteristics, were used to estimate associations between PAP treatment or adherence and new AD, DNOS, and MCI diagnoses.
In this sample of Medicare beneficiaries with OSA, the majority (78%) of beneficiaries with OSA were prescribed PAP (treated), and 74% showed evidence of adherent PAP use. In adjusted models, PAP treatment was associated with lower odds of incident diagnoses of AD and DNOS (odds ratio 0.78). Lower odds of MCI, approaching statistical significance, were also observed among PAP users (odds ratio 0.82). PAP adherence was associated with lower odds of incident diagnoses of AD (odds ratio 0.65). In conclusion, airway pressure treatment and adherence are independently associated with lower odds of incident AD diagnoses in older adults. Results suggest that treatment of OSA may reduce risk of subsequent dementia.