Should You Worry About Your Biological Age?
It reflects variations in the pace of aging
As a person ages, their physical and mental abilities gradually deteriorate while the risk of age-related diseases increases. However, aging does not affect everybody in the same manner. While one elderly individual may remain active, independent, and able to enjoy life, another may struggle with health problems and limitations of their daily activities.
What is the reason for this variability in the rate of aging? The concepts of chronological and biological age may help explain it.
Chronological age
Chronological age indicates the time that has elapsed since a person’s birth. With a higher chronological age, the risk of serious age-related diseases and mortality increases. However, the extent of age-related biological changes in each individual does not always correspond to their chronological age.
Biological age
Biological age reflects changes that occur in the structure and function of the body with aging. In simple words, it could be described as the age at which a person functions, and which their body resembles. In addition to chronological age, biological age has also been shown to contribute to the risk of mortality and age-associated disorders, including stroke, heart disease, and dementia. The rate of biological aging can be influenced not only by genetic (hereditary) factors but also by environmental and lifestyle factors.
Potential biomarkers of aging
Researchers have developed biomarkers that can capture certain aspects of biological age. They аrе based on molecular evaluations, phenotypic/clinical assessments, or composite measures combining both molecular and clinical tests. Some of the most widely investigated potential biomarkers of aging include epigenetic clocks, the frailty index, and composite measures.
Epigenetic clocks assess DNA methylation in specified sets of genes whose methylation closely correlates with age. The term DNA methylation indicates a chemical modification of DNA that regulates gene expression. A number of different epigenetic clocks have been developed. The earliest ones could predict chronological age. However, some more recently established epigenetic clocks have the potential to capture aspects of biological age.
Composite biomarkers, based on the analysis of a combination of clinical or molecular and clinical parameters have also been developed. For instance, some epigenetic clocks consider phenotypic/clinical parameters in addition to DNA methylation data in order to improve their ability to predict biological age.
Another approach focuses on health deficits that progress with aging. The term frailty refers to a constellation of signs indicative of health decline, rendering a person more dependent on others for their daily activities. The frailty index is a quantitative measure of frailty based on detecting the proportion of health deficits among a set of health-related items.
Challenges in the development of biomarkers for biological age
The development of aging biomarkers also faces challenges. First, the correlation between certain biomarkers of biological age may be weak, suggesting that they may measure distinct aspects of the aging process. In addition, it should be determined to what extent various biomarkers are active participants in the aging process or an accompanying finding. Finally, the degree to which potential effects of lifestyle interventions on biomarkers of biological age translate into changes of the healthspan (the number of years a person is healthy) and lifespan (the number of years a person lives) should be clarified in well controlled studies.
Prospects for the use of biomarkers of biological age
In addition to chronological age, biological age also contributes to the risk for development of age-related diseases and mortality. Biomarkers that can predict biological age may provide insight into individual health status and risks. In addition, in the long run, they may enable an evaluation of the effects of environmental and lifestyle interventions on aging. However, a number of open questions still remain to be answered in order to understand fully the role of individual biomarkers in the aging process.
