‘Understudied’ Middle Age Brain Changes Could Predict Dementia Risk

Understudied middle-aged brain changes could predict a person’s risk of dementia, according to a new study.

The study published in the journal Trends in Neurosciences looked at evidence from human and animal-focused studies to analyze the brain at what is deemed “middle age.” They reviewed “emerging evidence” that indicates how “midlife is a period defined by unique central and peripheral processes that shape future cognitive trajectories and brain health.”

The authors stress that that “previously understudied period of life” be given renewed consideration.

“Science has historically focused on older age, when the effects of time and disease are most pronounced. Unfortunately, by then, it’s often too late to intervene. This highlights why early detection is so important,” study authors neuroscientist Yvonne Nolan of APC Microbiome Ireland at University College Cork and Sebastian Dohm-Hansen, a PhD student, said in a joint statement to Newsweek.

“What we are now seeing is that many changes associated with the development of dementia or Alzheimer’s disease often emerge during middle age. Middle age is a period during which individuals are more sensitive to the impact of environmental and lifestyle factors. It is associated with weight gain, high blood pressure and increased risk of cardiovascular disease and diabetes,” they said.

“High blood pressure during middle age is one risk factor that is well-known to be prognostic of future dementia risk. Science is also finding that the effects of some genetic risk factors for Alzheimer’s disease manifest during middle age. One example of this is the risk gene APOE and its effect on memory for everyday events. Those carrying the risk gene show a faster decline in memory during middle age but not necessarily prior to it.”

The brain changes during middle age, usually between 40 and 65. The middle-aged brain is understudied, but the authors note in the study that it could hold clues to cognitive decline.

This is because at this time in life, the brain shifts and goes through molecular and cellular changes. The overall structure of the brain also changes, as the hippocampus—an area of the brain associated with memory—shrinks. As this happens, the connectivity between the hippocampus and other regions of the brain also shrinks.

Gene expression, in the brain and other parts of the body, can also undergo changes during middle age. The authors note in the study, evidence that suggests how these changes to other areas of the body can also hold clues into brain health and cognitive decline.

“Middle age appears to be a period of greater change than previously thought, and this change is likely relevant for future cognitive aging,” the authors’ statement said. “If science can pinpoint these changes during middle age, we may be able to better prevent and or even treat dementia and unhealthy cognitive aging. Critically, in midlife, the window of opportunity for intervention is still open compared to more advanced age.”

The study notes to some evidence that suggests exercise can help prevent cognitive decline, and promote “health cognitive aging” as a person goes through middle age.

“It will be important to understand what is unique to middle age compared to other periods of life. This is because risk factors and disease biomarkers have been found to evolve throughout the lifespan,” the authors said. “If we can establish reliable, early biomarkers of future cognitive decline, we can potentially increase the window of opportunity for prevention and intervention.”

“You can be biologically younger or older than your chronological change. Research in the last years has found that measures of biological age predict current and future health better than chronological age in years. This is because individuals age at different speeds, and this speed can change throughout the lifespan,” the authors continue.

For instance, a person’s biological ‘rate of aging’ during middle age was recently found to be strongly associated with both cognitive and physical health. It was even associated with how old the person was rated to look by others. Therefore, research which focuses on how individuals change over time, as opposed to merely comparing groups of different ages will serve as a better basis for conclusions about what separates healthy from unhealthy changes as we age.”

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