Poor sleep increases risk of Alzheimer's, research reveals -- the guardian

Quality of sleep, rather than quantity, linked with buildup of proteins clogging up brain and increasing the risk of disease Prolonged periods of poor sleep could increase the risk of Alzheimer's disease, although quality, not quantity, is at the root of the issue, research has revealed. While previous research has revealed that bad sleep can increase levels of proteins involved in Alzheimer's disease, known as beta-amyloid and tau, it was unclear which aspect of shut-eye was behind the uptick....
https://www.theguardian.com/science/2017/jul/10/poor-sleep-increases-risk-of-alzheimers-research-reveals