Association Between the Sleep Apnea Specific Hypoxic Burden (SASHB) with Incident Neurocognitive Impairment

2021 Focused Projects Grant for Junior Investigators

Gonzalo Labarca Trucios, MD
Brigham and Women’s Hospital

Key Project Outcomes

During the study period, we determined the association of different novel Obstructive Sleep Apnea (OSA)-driven metrics with the risk of incident dementia, including two different community-based cohorts in the National Sleep Research Resource (NSRR). We already know that obstructive sleep apnea is a prevalent disease with several comorbidities. OSA patients who are not treated probably have an increased risk of dementia, neurocognition impairment, cardiovascular disease, and other worse health outcomes. However, the apnea-hypopnea index (AHI) is a frequency-based metric that doesn’t provide information about the physiopathology of the disease. In this project, we saw different OSA-driven metrics beyond the AHI. The main result of this grant showed high arousal intensity, as measured by the number of electroencephalographic arousals per hour of sleep, was independently associated with an increased risk of incident dementia in 2 independent cohorts of individuals with obstructive sleep apnea. This association remains significant after adjustment by other cofounders. In the MrOS cohort, including 1136 older males with a median follow-up of 10.7 years; each 1 standard deviation (SD) increase in arousal intensity was associated with a 23% higher risk of incident dementia (95% CI, 0 – 50; P < 0.05). To confirm this association, we analyzed the MESA cohort, including a 1923 individual with a median follow-up of 6.8 years. In the MESA cohort, 3.5% of men experienced arousal events, and each increase in arousal intensity was associated with a 29% increased risk of incident dementia (95% CI, 1 – 65; P < 0.05).