Alzheimer's Research UK has stressed it was "hard to know the underlying reason" after a study linked a popular sedative to an increased risk of developing Alzheimer's.
Benzodiazepines have been shown to cause memory problems as part of their side effects and so it is difficult to tease out cause and effect in studies such as this.
We need more long-term research to understand this proposed link and what the underlying reasons behind it may be.
A new study "reinforces the suspicion of an increased risk of Alzheimer-type dementia among benzodiazepine users, particularly long-term users," French and Canadian researchers said.
The scientists identified 1,700 elderly people with Alzheimer's disease and more than 7,000 healthy people for comparison.
Past use of benzodiazepines for three months or more was associated with an increased risk of developing Alzheimer's, according to the study's results.
The risk varied between 43% and 51% and the strength of association increased with the longer exposure, they said.
A popular sedative has been linked with an increased risk of developing Alzheimer's disease in a new study.
Benzodiazepines, which are widely prescribed to treat anxiety and insomnia, have been associated with a heightened risk of developing the condition, particularly for long-term users, according to researchers.
Researchers cautioned that unwarranted long-term use of the drugs should be considered a public health concern.
The study, published in The BMJ, examined data from a health insurance database in Quebec.
Professor Carol Brayne, from Cambridge University's Institute of Public Health, said Alzheimer's could be tackled simply by becoming more active:
Simply tackling physical inactivity, for example, will reduce levels of obesity, hypertension and diabetes, and prevent some people from developing dementia as well as allowing a healthier old age in general - it's a win-win situation.
The development of a quick, cheap, non-invasive test to detect Alzheimer's would be an important step in helping people to receive an early diagnosis, the head of science at Alzheimer's Research UK has said, after new research suggests that regular eye tests could help detection.
It is difficult to diagnose Alzheimer's disease accurately and, in many cases, by the time the symptoms have developed, damage has already been going on in the brain for a number of years.
It is too soon to determine whether these types of tests will be useful for diagnosis of dementia and we would need to see the results of larger trials before drawing any firmer conclusions.
Regular eye tests could "complement" existing procedures as an initial screen in diagnosing Alzheimer's, the Australian science agency the Commonwealth Scientific and Industrial Research Organisation has said. Shaun Frost, who led one of the studies, added:
If further research shows that our initial findings are correct, it could potentially be delivered as part of an individual's regular eye check-up.
The high resolution level of our images could also allow accurate monitoring of individual retinal plaques as a possible method to follow progression and response to therapy.
Regular eye tests could in future be used to diagnose early-stage Alzheimer's, new research suggests.
Early trials of two different techniques show that a key Alzheimer's biomarker can be identified in the retina and lens of the eye.
Both methods were able to distinguish between probable Alzheimer's patients and healthy volunteers with a high level of accuracy.
Although the research is still at an early stage, further work could see such tests used as a first step in identifying individuals with Alzheimer's. Early diagnosis of Alzheimer's is essential to developing effective treatments that do more than alleviate the condition's symptoms.
A new blood test based on 10 "biomarker" proteins will make it possible to test new treatments at an early stage of Alzheimer's progression.
Writing in the journal Alzheimer's & Dementia, researchers from King's College London describe how they investigated 26 proteins previously associated with Alzheimer's disease.
They analysed blood samples from 476 confirmed Alzheimer's patients, 220 individuals with "mild cognitive impairment" (MCI) who experienced occasional memory loss, and 450 healthy elderly people.
In the vast majority of cases, memory lapses do not lead to Alzheimer's. But the researchers identified 10 blood proteins that appeared in 87% of MCI patients diagnosed with the disease within a year.
A blood test that can predict the onset of Alzheimer's disease before recognisable symptoms appear could become available in two years, scientists have said.
The test, likely to cost £100 - £300, can show with almost 90% accuracy which individuals suffering from mild memory loss are going to develop Alzheimer's within a year, researchers suggest.
Trials of drugs to halt or reverse Alzheimer's have all ended in failure so far. Therapies exist that can reduce its symptoms, but they only work for a short period of time and are not very effective.
Scientists believe a major reason for the lack of progress is that trial patients are being recruited too late, when their disease is already far advanced.
Dr Doug Brown, the Alzheimer's Society director of research and development, said people "must be given a choice about whether they would want to know, and fully understand the implications" of a test that could predict the onset of the disease.
We asked users of the ITV News Facebook page whether they would want to know in advance if they were likely to develop Alzheimer's.
- Dawn Kinsley: "One of the worst diseases going. So I would want to know, then I can get together my 'care' plan, have some 'careless' good times while I still remember and can enjoy."
- Mechelle Thomson: "Only to prepare my family so they would know what to expect. A little education could go a long way."
- Michael King: "How depressing knowing that you're going to get it in advance and being able to do little about it. I'd rather not know."