The loss of a child, divorce, getting fired and other stressful life events can cause the brain to age by at least four years, U.S. researchers have found.
According to a series of studies presented at the 2017 Alzheimer’s International Conference (AAIC 2017) in London, early life stress and neighbourhood conditions seem to enhance the risk of developing dementia later in life.
The University of Wisconsin study concluded that one major life stress event equals four years of cognitive aging. They also found that African Americans are the racial group most at risk because they experience, on average, over 60 per cent more of such events in their lives than non-Hispanic Caucasians.
The study looked at 1,320 adults, 1,232 of whom were Caucasian. Eighty-two were African Americans.
The goal was to look at how stressful life events like the ones mentioned above – as well as the impact of combat and growing up with a parent who abused alcohol – affected these two groups of people. Other types of conflicts researchers looked into were educational difficulties, interpersonal conflicts, financial insecurity, legal and justice system issues, serious health events and psycho-social and/or physical trauma.
Participants were asked to fill out a questionnaire about stressful experiences. Afterwards, they completed cognitive testing to measure memory and problem-solving abilities.
That’s when researchers found that – despite race – stressful events were associated with declining late-life cognitive function. However, when race was taken into consideration, African Americans were found to experience the most stressful events throughout their life – and it was these experiences that were linked to poorer memory and thinking skills in older age.
A second study by researchers at the University of California, San Francisco and Kaiser Permanente Division of Research made similar conclusions linking African Americans with a higher risk of dementia later in life.
The study looked at race specific infant mortality rates in 1928, specifically within the birth states with more than 6,200 members of the Kaiser Permanente Northern California health system.
Members born in the 10 states with the highest rates of infant mortality for their race were grouped as being born in states with the highest infant mortality rates. Researchers then linked that information with medical records to see if people born in these states were at a higher risk of dementia.
According to the results, African Americans born in states with the highest levels of infant mortality had a 40 per cent higher risk of dementia compared to African American from other states. They also had an 80 per cent higher risk compared to Caucasians not from those states, another study out of northern California concluded.
“These studies were done with U.S. data, but they add weight to the global body of evidence around disadvantage and dementia risk, which is an issue government around the world grapple with, and one that requires coordinated action,” Maria Carrillo, Alzheimer’s Association chief science officer, said in a statement. “For a racially diverse nation like the United States, and to address Alzheimer’s and dementia on a global scale, these findings support the need for targeted interventions, whether preventative or service-driven, to help address the gaps we know exist – and for more research.”
These findings aren’t the first to link stress in life to an increased risk of dementia in old age.
A 2010 study by the University of Gothenburg, which lasted 35 years, reported a link between stress in middle age in women and late-life dementia.
Stress in this study was defined as a sense of irritation, tension, nervousness, anxiety, fear or sleeping problems that last a month or more due to either work, health, family or other such problems.
The risk of dementia in women who reported reoccurring periods of stress in middle age was found to be 65 per cent higher than those who did not.
Researchers at the Baycrest Centre for Geriatric Care in Toronto also issued a warning earlier this year that people need to reduce any chronic stress and anxiety in their lives, or they risk increasing their chances of developing dementia.
Researchers say experiencing anxiety, fear and stress is normal when it’s occasional and temporary. But when those emotions become more frequent and chronic and interfere with daily life, then it can impact one’s immune, metabolic and cardiovascular systems, as well as lead to a gradual decline of the brain’s hippocampus – the crucial part of the brain responsible for long-term memory and spatial navigation.
According to the Alzheimer Society of Canada, there are an estimated 564,000 Canadians living with dementia – that number is expected to jump to 937,000 in the next 15 years.
Every year 25,000 new cases of dementia are diagnosed. There are currently about 16,000 Canadians under the age of 65 living with the disease.