“It’s not how old you are. It’s how you are old.” – Jules Renard
Even as life expectancy continues to rise worldwide (especially in developed nations), we are still preoccupied with living even longer. Which is why the anti-aging market is already expected to reach nearly $300 billion by 2024. But aging is a far more complex process than most people appreciate, especially since we begin aging before we are even born. Not only does growing older involve gaining a few more wrinkles or graying hair, but aging in humans affects us at all levels, from biological changes to changes in our mental outlook, our hopes, our expectations, and how we interact with the people around us.
For the 8th year in a row I co-organize the the pharmaceutical industry’s largest forum on aging research, the Aging Research and Drug Discovery forum and it gives me a front-row perspective on the industry. And while there are many breakthroughs in the many areas of basic science and even translational medicine, especially in the biomarkers of aging, and there are interventions that show a lot of promise, it is hard to make any actionable recommendations on how to dramatically slow down of reverse biological aging. At the very least, these would not be available to the average consumer for quite some time. However, there is one aspect of aging that we may be able to control and that is psychological aging.
How Do We Measure Aging?
While we all age at different rates, researchers have identified numerous biomarkers allowing for more precise measurement of age-related changes in the body that are often more accurate than measurement of chronological aging alone.
Among the most essential biomarkers are epigenetic clocks which can be estimated based on key DNA -methylation (DNAm) patterns. Epigenetic age is particularly valuable compared to chronological age since individuals showing accelerated epigenetic aging are much more vulnerable to cognitive decline, dementia, and a higher risk of mortality as well. By contrast, individuals showing slowed epigenetic age compared to chronological age demonstrate increased physical and mental fitness and a longer life expectancy overall.
Other biomarkers which have been identified include telomere attrition, MRI brain imaging, blood chemical parameters, and metabolic concentrations, all of which can be used to predict biological aging. Collectively known as “deep aging clocks”, these biomarkers are already broadly used in clinical research, the insurance industry, plus a soaring number of consumer applications. Also, the increasing use of machine learning algorithms and deep neural networks to interpret these biomarkers means that personalized medical techniques to address various age-related conditions may be just around the corner.
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Is Aging Psychological as well as Biological?
But, along with biological markers of aging, it is also important to recognize that we age on the psychological level as well. This also includes the impact of significant life events, both pleasant and unpleasant, have on our goals, beliefs, values, principles, and how we behave towards others.
Also known as subjective age or age identity, an individual’s psychological age is based on whether they perceive themselves as younger or older than their chronological age and how this perception affects health decisions in general. Research has certainly demonstrated the important role that emotional well-being and subjective age can have on health as people grow older.
For example, a recent research study has shown that older subjective age is linked to accelerated epigenetic aging suggesting a strong reciprocal relationship. Subjective aging is also closely tied with life satisfaction, though, interestingly enough, research suggests that too great a discrepancy between subjective and chronological age can be detrimental as well.
Other psychological factors that have a powerful impact on long-term health and aging include key personality traits such as neuroticism (the degree to which a person experiences the world as threatening and unsafe) and conscientiousness (the tendency to responsible and well-organized) both of which are part of the Big Five personality model currently dominant in psychology.
Along with personality traits, attitudes towards aging, such as how individuals perceive growing older and social and cultural stereotypes about age, can also influence health outcomes.
A longitudinal study that came out last year in the journal Psychology and Aging specifically examined the role that neuroticism, conscientiousness, and attitudes towards aging had on a large sample of German adults followed over a twenty-year period. Results showed that low neuroticism scores and positive attitudes about aging were strongly linked with physician ratings of physical health. Overall, however, the best health outcomes for seniors were in individuals with positive attitudes about aging combined with high conscientiousness scores.
It is also important to consider that subjective aging can vary widely across different populations around the world. An intriguing new meta-analysis recently published in the journal Psychology and Aging combined data from hundreds of studies and well over a million people worldwide. Results showed that adults over the age of forty and older adults tended to feel on average between 6.4 and 21.1 years younger than their chronological age, a gap which appears to increase steadily with time. Conversely, children and adolescents typically viewed themselves as being much older than their chronological age.
Compared across different geographical regions, the greatest discrepancy between subjective and chronological age was found in North America, followed closely by Western Europe and Australasia/Oceania. The smallest discrepancy was in African adults, which may relate to the overall quality of life and cultural/economic factors.
Understanding Future Time Perspective
But another factor closely linked to subjective age deals with our future time perspective, or the amount of time we feel we have left to us to accomplish important goals in our lives. As we move through different life stages, we become more acutely aware that time is passing for us, and it becomes more important than ever that we make the “right choices,” as well as feeling the need to evaluate our lives based on our successes and failures.
Although we know that we will grow old and die someday, that scarcely seems important in the first two or three decades of our lives. By the fourth or fifth decade, however, that far-off horizon when death or old age will overtake us seems much closer and, almost inevitably, our goals and long-term plans will change as well.
To explore this changing time perspective, Dr. Laura Carstensen of Stanford University proposed a social-emotional selectivity theory which suggests that the goals we set for ourselves are largely based on how we perceive the amount of time we have to pursue these goals. Younger people, who know they have decades of life ahead of them, are often more likely to pursue knowledge-based goals (such as a high school senior choosing a college major). This also means accepting that more emotionally based goals will need to be delayed until after graduation. While they may adopt other goals along the way (such as romantic relationships and even marriage), they continue to take the long view meeting these goals.
As we grow older, our social networks will become smaller as we shift from numerous friendships towards deeper affiliations with a few close friends. Research has also demonstrated that the emotions we experience will become more easily managed while negative emotions will become more infrequent (until very old age). Our sense of psychological well-being and life satisfaction will become greater as well due to an accumulated lifetime of experience dealing with serious crises and daily hassles. While we may well pursue goals such as going back to school as seniors, our motivation will have changed from pursuing a far-off degree to attending classes for personal enjoyment.
What Role Does Psychological Aging Play in Health?
These different approaches have yielded intriguing research findings suggesting that our perceived age can play an important role in coping with physical disease and how successfully we function as we grow older. Numerous studies show that the older we become chronologically, the younger we feel we are inside, which appears to be equally true for both men and women. Studies examining different biomarkers also show a significant relationship between feeling younger and improved health, including decreased obesity and inflammation, increased liver enzymes, increased grip strength, body mass index. Elderly individuals with a younger subjective age also showed evidence of younger brain age, including a higher volume of grey matter in key brain regions as well as retaining cognitive abilities in later life.
One of the most productive research areas into psychological and subjective aging deals with how stressful life events can impact overall health and make our bodies age faster. Many studies already have shown that too much adverse stress can trigger a range of different physiological changes such as the production of pro-inflammatory cytokines, cortisol, prolactin, and adrenocorticotropic hormone, all of which are associated with the body’s “fight or flight” response to traumatic situations. One 2009 study of military veterans has also linked post-traumatic stress disorder to increased subjective age and physical health issues, memory problems, and weight gain. Subjective age has also been associated with aging biomarkers such as shortened leukocyte telomere length, suggesting that increased subjective age can affect aging well beyond what could be expected by chronological age alone.
Given that depression is one of the most common mental disorders worldwide, researchers have also focused on the role that severe depression can have on subjective and biological aging. Much like acute and chronic stress, research has also linked depressed to increased serum cortisol levels along with various somatic, behavioral, and cognitive impairments. Though depression can strike at any age, it is especially debilitating in seniors and can often exacerbate other medical problems they may develop.
In more extreme cases, severe geriatric depression is often misdiagnosed as dementia (or vice versa). Longitudinal studies have also found that older subjective age can predict serious medical problems and depression later in life.
The Problem with Measuring Psychological Aging
Despite extensive research linking psychological age and subjective age with health, there is still the problem of how they can be effectively measured. As we have already seen, biomarkers for aging can be established in many different ways but doing the same with more subjective measures is much more difficult.
Historically, research studies looking at subjective age simply involved asking research subjects a single basic question: “What age do you feel?” Another approach involves asking people whether they felt younger, older, or the same as their chronological age, or else asking them what their ideal age might be, i.e., “if you could choose your age, what age would you like to be?” Yet another approach involves using digital photographs or physical appearance to determine how old research participants see themselves as being.
Despite this lack of consensus among researchers looking at psychological aging, new approaches involving machine learning and neural networks may well pave the way towards a better understanding of subjective aging and how it relates to health.
Measuring Psychological and Subjective Aging Using Artificial Intelligence
As we have already seen in a previous section, new tools for evaluating different biomarkers for aging are already promising to usher in a new age of personalized medicine. But would it be possible to do the same with measures of subjective aging?
A new study recently published in the journal Aging suggests that it can. In this study scientists at Deep Longevity, recently acquired by Regent Pacific, used machine learning to evaluate the data taken from a large open U.S. longitudinal study of health and well-being. The research team examined different aspects of chronological and subjective age using neural networks. These aspects included health status, relationship quality, perceived life changes, occupational concerns, community involvement, personality traits, psychological beliefs, demographic features, and perceived well-being.
In this study, the interdisciplinary group developed two “psychological clocks”: PsychoAge, which predicted chronological age in the healthy state, and SubjAge, for predicting perceived age, also commonly referred to as subjective age. Both clocks proved to be powerful predictors of chronological age and subjective age. They were also significant predictors of all-cause mortality though SubjAge was a more decisive risk factor.
One important finding about both clocks was that they could be “reversed” using social and behavioral interventions. This using this research to help individuals to develop healthier behaviors and have a more positive life outcome as a result.
The most important finding that can be employed in our daily lives was that the optimistic attitude to life and personal well-being plays the most important role in prediction of both the psychological and subjective age. This attitude may be
What Does the Future Hold for Psychological Aging Research?
In the same way that research into biomarkers of aging is being used to develop personalized medical treatments to help people live longer and healthier lives, we see that research looking at subjective and psychological aging holds similar promise for the future. But can significant life changes such as improvements in lifestyle choices, teaching people better ways to handle stress, and develop improved life satisfaction leading to longer lives in general? As we already see in numerous research studies, psychological aging clocks based on lifestyle and behavioral data may well prove to be just as impactful as biological aging clocks are in promoting longer and healthier lives overall.
Artificial Intelligence can be a very powerful tool for studying psychological aging and developing novel interventions to help reverse it, and prevent the onset of a plethora of associated diseases. I hope to cover this research in the following articles.
To learn more about aging research, I highly recommend attending the 8th ARDD conference in Copenhagen either on-site or online. It is organized by the University of Copenhagen and Columbia University. It is one of the largest conferences on aging in the world bringing together academic scientists, startups, venture capitalists, and pharmaceutical companies. In 2021 for the first time it will feature a workshop on the nascent field of Longevity Medicine to cover the recent advances in clinical research.