Figure 1. Stepwise exclusion process for MCI and AD subsets.

Survival analysis on age at MCI/AD onset was performed on 3 subsets defined by progressively stringent criteria for inclusion: the first subset (C1) excluded participants with missing data; the second subset (C2) excluded participants with ambiguous group allocation; and the third subset only contained participants with incident MCI or AD (C3). AD = Alzheimer disease; ADNI = Alzheimer's Disease Neuroimaging Initiative; BMI = body mass index; MCI = mild cognitive impairment; OSA = obstructive sleep apnea.