Alzheimer’s disease can progress silently for nearly a decade before it is diagnosed and treated. A French research team has now managed to identify symptoms that may appear more than 15 years before the disease becomes clinically visible.
Alzheimer’s affects nearly one million people in France. It primarily impacts older adults: it is very rare before age 65 and affects almost 15% of people over 80. Alzheimer’s is a neurodegenerative disease in which nerve cells gradually deteriorate, leading to several symptoms that appear progressively. The best known is memory loss, but it is not the only one. Patients also experience impaired executive functions and difficulties with orientation in time and space. At present, the disease can neither be cured nor truly prevented. Our knowledge of its earliest signs remains very incomplete. By the time most patients are diagnosed, the disease is often already at an advanced stage.
A study involving 80,000 people
A French team has published the results of a large-scale study involving 80,000 patients in the prestigious journal The Lancet. Half of them went on to develop Alzheimer’s disease, while the other half formed a control group and did not develop any neurodegenerative condition over the study period.
The researchers examined the relationship between the onset of the disease and 123 different health factors using statistical analyses. Their results show a correlation between a list of ten conditions and the emergence of Alzheimer’s within 15 years. The first of these conditions is depression, followed by anxiety, exposure to significant stress, hearing loss, constipation, cervical spondylarthritis, memory loss, fatigue, falls and sudden weight loss.
Some of these conditions were already known to increase the risk of developing Alzheimer’s, such as depression or hearing loss. Others were much less expected, including cervical spondylarthritis or constipation.
Depression could be a precursor to Alzheimer’s disease. © Bits and Splits Adobe Stock
Just statistical links
The authors emphasise that their work highlights only statistical links, which do not prove cause and effect. A deeper investigation of the underlying mechanisms is still needed.
In addition, the paper does not clarify whether suffering from depression increases the risk of developing Alzheimer’s, or whether depression is itself an early symptom of the disease. Even so, this kind of information is extremely valuable for better understanding the illness and exploring ways to anticipate or delay its onset.
Next, the researchers plan to extend their analyses to a far larger number of medical records – 26 million – and to other degenerative diseases such as Parkinson’s disease, motor neurone disease (Charcot’s disease) and multiple sclerosis.
Stéphanie Le Guillou
Health journalist
With a PhD in Pharmacy and Cancer Biology, this expert has worked in hospitals, the pharmaceutical industry, and a healthcare communication agency.
Today, she pursues her passion for writing, creating medical content for the general public. She regularly contributes to Futura’s Health section, striving to make medical information more accessible.