More than a million people suffered from Alzheimer’s disease in France in 2019 and this figure will gradually increase in the coming decades, according to the Fondation Vaincre Alzheimer. Alzheimer’s disease is a neurodegenerative disease characterized by progressive and irreversible damage to the brain, which affects many cognitive functions, such as Memory, language, reasoning, or even learning. It represents 60 to 70% of cases of dementia according to the Pasteur Institute.
If age is the main thing risk factorother elements can play on the development of the disease such as the presence of cardiovascular risk factorsa lack of physical activity, poor eating habits, heavy alcohol consumption, or even repeated microtrauma of the brain, as in athletes for example.
Alzheimer’s: what impact do stressful life events have on the development of the disease?
But these are not the only environmental factors that can influence the onset of Alzheimer’s disease according to a study published on March 11, 2024 in the journal Annals of Neurology. His goal ? Assess the link between the presence of stressful events throughout life and the development of pathologies linked to Alzheimer’s disease years later. To do this, the researchers analyzed data from more than 1,200 people without cognitive disorders at the start of the study, but with a direct family history of Alzheimer’s. They tested their various biomarkers linked to Alzheimer’s disease and assessed their number of stressful life events, likely to lead to behavioral and psychological reactions, such as the death of a loved one, unemployment, or illness.
At the end of the study, the scientists noticed that higher levels of stressful events in childhood were associated with an increased risk of developing neuroinflammation at a later age. They also point out that inflammation is recognized as a key molecular response in neurodegenerative diseases like Alzheimer’s.
Stress and Alzheimer’s: it may not have the same effects on the brains of women and men
Researchers also noted that a large number of stressful mid-life events were linked to higher levels of β-amyloid protein, itself associated with the development of Alzheimer’s disease. However, they observed this relationship only in men, while in women a significant level of stressful life experiences was associated to lower volumes of gray matter in the brain. “Our results suggest that the mechanisms by which the factors of stress of life affect brain health in men and women are different: accumulation of amyloid proteins in men and brain atrophy in women“, Eider Arenaza-Urquijo, one of the study’s authors, said in a statement.
Separately, scientists observed that stressful events in the lives of people with a history of psychiatric illness were also linked to higher levels of β-amyloid protein and tau protein, both responsible for the onset of the disease. Alzheimer’s disease, neuroinflammation, and lower gray matter volume. According to the study’s researchers, this suggests that this population could be more sensitive to the effects of stressful moments, in particular because of poorer capacity to manage stresswhich would make them more vulnerable.
Alzheimer’s: results which underline the importance of the impact of stress on health according to scientists
According to the study’s scientists, these results show that certain periods of life can make people more vulnerable to the development of conditions in later years. “We know that midlife is a time when Alzheimer’s disease pathologies begin to accumulate, it is possible that these years represent a period of vulnerability where psychological stress can have a lasting impact on brain health“, Eleni Palpatzis, another author of this work, said in a statement.
Although more research is needed, these initial findings highlight the importance of the impact of lifelong stress on brain health, researchers say. “Our study reinforces the idea that stress could play an important role in the development of Alzheimer’s disease and provides initial evidence regarding the mechanisms behind this effect, but further research is needed to replicate and validate our initial results“, concluded Eider Arenaza-Urquijo.
Sources :
- Lifetime Stressful Events Associated with Alzheimer’s Pathologies, Neuroinflammation and Brain Structure in a Risk Enriched Cohort – Annals of Neurology – 11 mars 2024
- Stressful events in midlife might be a risk factor for Alzheimer’s disease in older ages – Barcelona Institute for Global Health – 3 avril 2024
- Alzheimer’s in a few figures – Fondation Vaincre Alzheimer
- Alzheimer’s disease: symptoms, treatment, prevention – Institut Pasteur
