In this study, the authors investigated the association between sleep apnea and risk of dementia based on a study on the use of Vitamin E and Selenium (1). Participants were assessed at 128 local clinical study sites during the clinical trial phase and followed-up. The results of the study showed that self-reported sleep apnea on dementia risk depended on APOE 4 status. When the allele was absent, baseline self-reported sleep apnea was associated with a 66% higher risk of developing dementia, whereas self-reported sleep apnea caused no additional risk. The authors conclude that sleep apnea may increase risk of dementia in the absence of APOE4. This may help prevention strategies for dementia or Alzheimer's disease in older men with sleep apnea.