Scientists found interrupted slumber raises levels of toxic proteins in our bodies that are tell-tale signs of the incurable disease.
The danger affects people in middle age, and is a big worry for those suffering serious conditions, such as sleep apnea.
Researchers from Washington University School of Medicine, in St Louis, Stanford University, in California, and Radboud University Medical Centre, in the Netherlands, studied the sleep patterns of 17 healthy adults aged between 35 and 65.
They found that disrupting sleep meant people had higher levels of amyloid, a toxic protein and key hallmark of Alzheimer’s, when they woke up.
The study did not test whether people went on to develop Alzheimer’s but their findings may explain why poor sleep has been associated with the onset of dementia.
Study author Dr David Holtzman said: “We showed that poor sleep is associated with higher levels of two Alzheimer’s-associated proteins. We think that perhaps chronic poor sleep during middle age may increase the risk of Alzheimer’s later in life.”
Yo-El Ju, assistant professor of neurology at Washington University, said: “The main concern is people who have chronic sleep problems.
“I think that may lead to chronically elevated amyloid levels, which animal studies have shown lead to increased risk of amyloid plaques and Alzheimer’s.
“At this point, we can’t say whether improving sleep will reduce your risk of developing Alzheimer’s.
“All we can really say is that bad sleep increases levels of some proteins that are associated with Alzheimer’s disease. But a good night’s sleep is something you want to be striving for anyway.”
Dr Doug Brown, of Alzheimer’s Society, said: “Research is emerging that indicates poor quality sleep may be associated with a higher risk of developing Alzheimer’s.
“Getting a good night’s sleep is important for a range of different health reasons.
“If you are worried about your sleep patterns, or your memory, it’s important to speak to your GP.”
The findings were published in the journal Brain.