Study identifies 10 factors linked to Alzheimer’s risk

Posted on March 02, 2022

Attempts to develop an effective treatment for Alzheimer’s have met with little success. Researchers are increasingly turning their attention to detecting the disease early.

The key to this strategy is to identify early, “modifiable” risk factors that doctors can target with drugs or other interventions.

Researchers at the Paris Brain Institute in France have now found statistical associations between 10 health conditions and a diagnosis of Alzheimer’s disease up to 10 years later.

Major depression was the earliest condition to be associated with a subsequent diagnosis of Alzheimer’s, appearing at least 9 years in advance.

Other conditions that the study linked to a later diagnosis of Alzheimer’s included:

anxiety
constipation
abnormal weight loss
a type of arthritis called cervical spondylosis
reaction to severe stress
hearing loss
sleep disorders

They also showed that falls and fatigue had links to Alzheimer’s risk.

The next step will be to determine whether these conditions help cause the disease or whether they are early signs of changes in the brain that are already happening.

“Diseases like Alzheimer’s can begin in the brain up to 2 decades before symptoms start to show,” said Katy Bray, Ph.D., told Medical News Today. Dr. Bray is a public engagement manager at Alzheimer’s Research UK and was not involved in the research.

“It is difficult to know how these conditions may contribute to the development of the disease or if they could also be very early symptoms,” Dr. Bray told Medical News Today.

How the study worked

The researchers analyzed the primary healthcare records of 20,214 people with Alzheimer’s disease in the United Kingdom and 19,458 people with Alzheimer’s in France.

They compared each person’s medical records with a control matched for sex and age who had not received a diagnosis of a progressive brain disease during the 15-year study period.

Out of the 123 health conditions they investigated, 10 had a statistically significant association with a diagnosis of Alzheimer’s disease 2–10 years later in France and the U.K.

Some of the conditions, such as depression, hearing loss, and sleep disorders, are already known risk factors for Alzheimer’s.

However, this study was the first to identify constipation as a possible risk factor. The link between the two conditions became apparent 7 years before the diagnosis of Alzheimer’s.

Interestingly, constipation is also associated with depression and is an established early sign of other brain diseases, such as Lewy-body dementia and Parkinson’s disease.

“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,” says Thomas Nedelec, Ph.D., the first author of the study.

“The question remains as to whether the health problems encountered are risk factors, symptoms, or warning signs of the disease,” he added.

The study had some notable limitations. For example, it was unable to take other risk factors that contribute to Alzheimer’s, including education level, ethnicity, socioeconomic status, and genetics, into account.