As age marches on, understanding and being aware of risk factors and taking action becomes crucial to potentially avoiding dementia on the horizon.

Brain imaging tools, more longitudinal data sets becoming available, and improvements in analysis have changed how we think about neurocognitive aging, its developmental roots, and its life course effects. The Scaffolding Theory of Aging and Cognition STAC) is a life course model first introduced in 2009. It proposes that adaptability and compensatory potential are ways that people can deal with neurocognitive challenges from their surroundings and brain circuitry growing or shrinking over time. New information about when potentially enriching and depleting factors impact brain health and scaffolding has important applications for life in middle age.

As people age, scaffolding helps keep cognitive functioning intact. There is evidence that cognitive engagement, exercise, and low levels of default network activity can make it easier to use this mechanism. The hypothesis offers hope for those seeking to prevent dementia in their later years. However, one element defies the hypothesis: how do we define middle age? Is it the number of birthdays we've had, or something we may be unaware of on a biological level?

Even in middle age, chronological age is not a good indicator of biological age. A study looked at a typical birth cohort in the community with no chronological age differences. The people in the study had a wide range of aging rates. The study measured “Pace of Aging” by tracking how 19 biomarkers related to the circulatory, metabolic, renal, immune, dental, and pulmonary systems lost function at ages 26, 32, 38, and 45.

One finding was that people in the study who had a faster Pace of Aging in midlife had more cognitive problems, lessened sensory-motor functional ability, and had negative views about getting older. An analysis confirmed the hypothesis that the Pace of Aging shows the cumulative, progressive, and gradual breakdown of organ systems that happens with biological aging. Therefore, biological age determines how quickly or slowly our body ages, which affects our brain functioning and cognition.

What might it be like if we could change this biological aging, which may outpace our chronological aging? There are about 12 modifiable risk factors that account for about 40% of dementia cases worldwide. This means that we might be able to avoid or delay dementia.

The risk factors can be seen as important in attempts to stop or forestall dementia, and it may be even easier in low- and middle-income countries (LMIC), where it happens more often. The recommended approach can be outlined as follows:

Maintain healthy blood pressure

Reduce exposure to air pollution and secondhand tobacco smoke

Prevent head injury

Limit the use of alcohol

Avoid smoking

Provide all children with primary and secondary education

Reduce obesity and maintain an awareness of weight control

Get sufficient sleep each day

Read, play board or card games

Learn to speak a second language

Continue socializing

Engage in physical activity and exercise

Being mentally, physically, and socially active in middle age and later life is important, but there is insufficient evidence that any one exercise protects against dementia. Hearing aid use lowers the extra risk that comes with losing your hearing and anxiety or depression. Long-term exercise in middle age and probably later in life may lower the risk of dementia by lowering the risk of obesity, diabetes, and heart disease.

Why an emphasis on children's primary and secondary education? According to research, general cognitive ability rises with education until late adolescence, when brain plasticity is at its highest. After age 20, there are a few more gains from education. This shows that cognitive stimulation is more important in the early years. Much of the effect seen later may be because people with better cognitive function seek out activities and education that stimulate their minds. The watchword here would be "stimulation," both mentally and physically.

Researchers and those who track healthcare advise planning for one's mental life earlier in life, and midlife is certainly one place to begin. If I were to state this succinctly, I would say, "Start early and maintain your efforts in all the areas outlined as potentially contributing to biological aging and dementia.” If you don't, you know what will happen.