Middle age and childhood stress linked to Alzheimer’s risk later in life

The Barcelona Institute for Global Health (ISGlobal) has led a study that associates stressful experiences in middle age with the risk of Alzheimer’s disease in later life. They have also found a link between childhood stress and brain inflammation in adulthood, a trait also associated with Alzheimer’s and other neurodegenerative diseases. The Barcelona Beta Brain Research Center (BBRC), a research centre of the Pasqual Maragall Foundation, has also participated in the study.

Dementia affects 50 million people worldwide and this number is expected to triple by 2050. The most common cause of dementia is Alzheimer’s disease, which presents with accumulation of various proteins in the brain (β-amyloid and phosphorylated tau), neurodegeneration, cognitive degradation and neuroinflammation (brain inflammation).

The research team monitored these Alzheimer’s biomarkers in a cohort of 1,290 people without cognitive degeneration but with a family history of the disease. They also monitored their stress, through interviews, and searched for the relationship between stressful life events and the presence of these biomarkers at older ages. A relationship has only been found in people who have suffered stress in middle age and childhood.

“Our results suggest that the mechanisms through which life stressors affect brain health in men and women are different: amyloid protein accumulation in men and brain atrophy in women”, explains Eider Arenaza-Urquijo, researcher at ISGlobal. While in middle-aged men stress causes amyloid protein accumulation at older ages, in middle-aged women an evolution to a decrease in grey matter is observed.

This decrease in grey matter has also been seen in people with a psychiatric history, along with the accumulation of tau protein and interleukin-6, which are also biomarkers of Alzheimer’s disease. These data suggest that people with a psychiatric history are more vulnerable to stressful life events, perhaps because they are less able to cope with them, and are therefore at greater neurodegenerative risk.