PERTH, Australia — If your job is always putting you in a bad mood, you’ll be doing your brain a favor if you take up a career that makes you happier. A new study concludes that having a stressful job may lead to Alzheimer’s disease.
Researchers at Curtin University in Australia say that work stress damages an area of the brain triggered during emotional pressure. Known as the HPA (hypothalamus-pituitary-adrenal) axis, it releases stress hormones, including cortisol. High levels have been linked to memory loss, and even shrinkage of gray matter.
“Chronic stress affects many biological pathways. There is an intimate interplay between exposure to it and the body’s reaction,” says senior author David Groth, a dementia expert and professor at the university, in a statement. “Genetic variations within these pathways can influence the way the brain’s immune system behaves leading to a dysfunctional response. In the brain, this leads to a chronic disruption of normal processes, increasing the risk of subsequent neurodegeneration and ultimately dementia.”
The Australian team identified a link between “psychosocial stressors” and Alzheimer’s in susceptible individuals. Examples include divorce, bereavement, prolonged illness, moving home — or a highly competitive work situation. Combined with genetic factors, it can make some individuals more prone to the devastating neurological disorder.
More evidence linking chronic stress to Alzheimer’s disease
The study, published in the journal Biological Reviews, is based on an analysis of previous evidence. It shows that stress fuels inflammation in the HPA, impairing clearance of rogue proteins known as beta amyloid and tau. They clump together in the brain, destroying neurons. Immune cells called microglia are unable to kill them.
“Microglia can be primed by chronic stress leading to an exacerbated pro-inflammatory immune response,” the authors write. “Genetic risk factors may further render microglia more susceptible to the effects of environmental stressors.”
Short-term, temporary episodes of fear and stress such as those experienced by people before an exam, job interview or driving test are part of everyday life. But long term feelings of stress and anxiety due to work or personal problems can “wreak havoc” on immune cells and damage the brain.
It adds to growing evidence recognizing that chronic stress as a risk factor for the increased cognitive decline seen in Alzheimer’s.
“This relationship may be mediated by dysregulated HPA axis and cortisol levels,” the authors write.
Stress management may be more vital to our health than realized
Cortisol is known to affect cognition. But the molecular underpinnings are not yet fully understood. The findings could help identify those at greatest risk. Prescribing drugs earlier improves the chances of success.
Epidemiological studies suggest that PTSD and depression can lead to dementia. A study of women tracked for 35 years found those stress during midlife were around twice as likely to go on to develop Alzheimer’s.
“There remains a need for a greater understanding of how genetic factors influence reactivity to cortisol and chronic stress and may interact with specific cell types, such as microglia, to promote Alzheimer’s,” says Groth, per South West News Service.
Mutations that render a carrier more susceptible to the effects of stress and cortisol could determine how microglia enter a ‘primed’ state. It is an example of how genetic and environmental factors work together to drive dementia.
“It is important to consider that multiple subsets of microglia, with distinct genetic signatures, exist within the brain as these maybe impacted differently by genetic and stress interactions,” says Groth.
The phenomenon could lead to the development of better drugs that target microglia, tau or beta amyloid, as well as stress management strategies.
SWNS writer Mark Waghorn contributed to this report.