Editor’s Note: Bonnie Whitehead, MSc. (Psychology) continues her new Country Guide column demonstrating how the rapidly evolving science of psychology can improve your business and personal farm success. Imagine if your age wasn’t measured in years, she writes below, but in health and vitality.
My son was nearly 12 lbs. at birth. When he was born, the obstetrician held him in the air, one hand on my son’s bottom, one hand cradling his head and neck, and said, “This is a record breaker!”
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He was so long the measuring tape in the delivery room was not long enough to take his length measurement. The next day the nursing staff finished the job of compiling the usual birth stats by taping two measuring tapes together.
The day after he was born, the obstetrician told me my son looked like about a three-month-old.
And so he did. My son’s physical development (weight, height and appearance) seemed to mismatch his age.
A similar situation can happen at the other end of life with regard to the cognitive vitality and age of older adults. Everyday observers and scientists have long noted that chronological age does not always match well with older adults’ cognitive vitality (i.e. mental acuity; Anstey, Lord & Smith, 1996).
For instance, despite advanced age, some older adults maintain high levels of cognitive functioning. On the other extreme, social, psychological and biological factors may combine in ways that are related to accelerated decline and impairment in cognitive status (Dixon, 2011).
Imagine if your age wasn’t measured in years, but in health and vitality. Some people, although very elderly, may have superb health. That would put their biological age at younger than their age in years.
That is the basis of what researchers call “BioAge.” BioAge is intended to be an indication of functionality, vigour or health, that is measured not by years, but by that status of special markers (i.e. “biomarkers”) that relate well to the most basic, biological systems and processes that underpin aging (DeCarlo, Tuokko, Williams, Dixon and MacDonald, 2014; MacDonald, Dixon, Cohen & Hazlitt, 2004).
Here’s how at least some biomarkers may likely work:
Many diverse factors have an impact on aging-related cognitive change (i.e. stability, improvement or decline). These factors act on the brain in ways that either support or deteriorate neurological health (Dixon, McFall, Whitehead and Dolcos, 2013).
Factors that affect cognitive functioning often work by affecting levels of inflammation, vascular integrity and oxidative stress in the brain (DeCarlo et al., 2014). Interestingly, these same processes are importantly connected to aging-related processes elsewhere in the body, including aging-related decreases in muscle mass and sensory functioning (DeCarlo et al., 2014).
For instance, inflammation and oxidative stress are two mechanisms behind aging-related loss in muscle mass (i.e. sarcopenia), which may lead to decreased grip strength. Levels of inflammation and oxidative stress that promote the loss of grip strength may simultaneously affect the brain in ways that may negatively affect cognitive functioning (DeCarlo et al., 2014).
The upshot? Some factors that are clearly related to physical health and vitality (like grip strength) are also associated with cognitive status and resiliency (common cause hypothesis; MacDonald et al., 2004).
Observers may wonder: Are there any biological markers known presently that could be used to predict who will get a neurodegenerative disease like Alzheimer’s?
That question is now a hot topic for dementia researchers, not least because if such biomarkers could be identified, they may act as important targets for Alzheimer’s prevention. Presently, important themes are emerging and being refined in this area of research.
Here’s a snapshot of information researchers know so far:
The Victoria Longitudinal Study, a large-scale study of human aging based in Edmonton, Alta., recently assessed the long-term cognitive status and change of a large group of healthy older adults (McFall, McDermott and Dixon, 2019). These adults did not have cognitive impairment, but like any group of older adults, they varied widely in terms of their level of cognitive ability, and their rate of change in cognitive ability over time.
Scientists were able to divide these older adults into three groups based on their level of cognitive performance and the pattern of change in cognitive abilities: A high-functioning group that showed above average and stable memory functioning over time, a normal aging group, and a lowest functioning group that had the lowest memory functioning and the greatest loss of memory functioning over time.
The scientists looked at 17 different biomarkers and lifestyle variables to see if they were useful for predicting individuals’ membership in each of the three groups. The results were complex, but the overall picture is one where specific biomarkers within certain age ranges predict important memory differences and change across time.
This pattern of results makes sense, given a recent report that important targets for dementia risk prevention may also vary by age (Livingston et al., 2020). Early in life, higher education may pay the most dividends in terms of preventing late-life dementia. In midlife, hearing loss, hypertension and obesity may be key modifiable risk factors. In late life, diabetes, smoking, depression, physical inactivity and social isolation may be the most powerful targets for dementia prevention (McFall et al., 2019).
This evidence seems to support the idea that the goal of high-functioning cognitive ability in late life is a lifelong endeavour (Livingston et al., 2020), with particularly important targets for ensuring cognitive health emerging sequentially across the life course.
Some important takeaway messages stand out:
There is no doubt of an important connection between the health of the body and the health of the brain (DeCarlo et al., 2014). Generally speaking, adults should not underestimate the positive effect managing their health and overall vitality may have on maintaining high-level cognitive functioning throughout life (Livingston et al., 2020).
Cognitive functioning in late life is likely affected by multiple risk and protection factors. Studies have converged on certain modifiable risk factors for dementia prevention that have special importance at certain stages of the life course: early life (education), midlife (hearing loss, hypertension, obesity) and late life (diabetes, smoking, depression, physical inactivity, social isolation) (McFall et al., 2019).
By the way, are you wondering what your grip strength may mean about your cognitive abilities? In aging research, grip strength has often been combined with other indicators of physiological functioning (blood pressure, pulmonary functioning and body mass index, for example) and sensory functioning (hearing and visual acuity, for example) to form a composite biomarker measure. A 2004 study showed that one such biomarker-type combination of physiological and sensory measures, including grip strength, was an excellent predictor of aging-related cognitive change over 12 years, independent of actual age in years (MacDonald et al., 2004).
