Alzheimer's disease could be preceded by a number of medical conditions, according to new research published in the Lancet.
The study linked 10 health conditions to the disease, including major depressive disorder and constipation.
Though researchers said it is unclear whether the linked conditions are symptoms, risk factors, causes or warning signs of Alzheimer's, according to the Daily Record.
READ MORE: Two types of food to cut down on in your diet if you want rapid weight loss
Alzheimer's disease is a brain disorder that leads to memory loss and thinking skills worsening over time.
It is believed to account for up to 70% of dementia cases.
The study's researchers deemed Alzheimer's one of the "principal health challenges of the 21st century".
The cause of Alzheimer's is unknown and there is no cure.
However, the NHS says there are a few established things thought to increase your risk of developing the condition: increasing age, family history, untreated depression, and lifestyle factors and conditions associated with heart disease.
A study in The Lancet Digital Health, aimed to confirm well-known dementia risk factors and discover others.
The research analysed Alzheimer's patient information, examining data collected from 20,214 UK patients over a 24 year period and 19,458 people in France covering 21 years.
The study is the first to identify constipation as a possible risk factor appearing seven years before Alzheimer's diagnosis.
Health conditions linked to later Alzheimer's diagnosis
- Major depression
- Anxiety
- Constipation
- Abnormal weight loss
- Reaction to severe stress
- Sleep disorders
- Hearing loss
- Type of arthritis called cervical spondylosis
- Falls
- Fatigue
Major depressive disorder was discovered as the earliest associated condition, appearing nine years before Alzheimer's diagnosis.
Thomas Nedelec, Ph.D., the first author of the study, said: "The connections made allowed us to confirm known associations, such as hearing problems or depression, and other less-known factors or early symptoms, such as cervical spondylosis or constipation.
"The question remains as to whether the health problems encountered are risk factors, symptoms, or warning signs of the disease."
Receive newsletters with the latest news, sport and what's on updates from the Liverpool ECHO by signing up here
