How Biological Age Beats Counting Birthdays for Predicting Life Expectancy
Asking someone their age is a simple question. After all, all we really want to know is the time that has passed since their birth, the chronological age. However, the answer to this seemingly simple question may be more complex.
A person who doesn’t look their age suggests that his or her “apparent age” may be lower or higher than the chronological age.
Sometimes our view is influenced by a person’s apparent psychological or emotional age, or our impression of more superficial aspects like their behaviour, style of dress or musical taste.
Thinking about a person’s by chronological age only puts their life into age context – young, older or elderly – and may just hint at remaining life expectancy. This is because age measured by time alone does not take account of biological age.
Biological age uses quantifiable determining scientific factors – blood pressure, cholesterol, metabolism, liver and kidney function, or cardiovascular and respiratory health. Using biological age allows us to think about how the continued development of a person’s health during their life influences life expectancy.
In crude terms how many years are “worn off” the possible total expectancy compared with a standard person of the same age. This is a primary concern of Life and Health insurers.
Research has suggested the lengths of telomeres – the regions capping the ends of chromosomes – have a direct relationship to the biological age of the body’s cells. So telomeres could be the primary individualized biomarker of life expectancy, which implies they could be measured to provide a scientific basis for determining biological age of a person.
Several influences, including health and hereditary factors, can affect telomere length changes over time. Whereas we are unable to influence what we inherit, we can control the factors that affect our health. For example, by eating a “Mediterranean” diet rich in vegetables, fruit and fish, taking regular exercise, living in an environment with low levels of pollution or stress, limiting alcohol or coffee and avoiding smoking.
Telomeres could provide a life expectancy measurement before any deterioration in health is noticed. Other DNA markers related to longevity are currently under study. In future research into genetics and DNA will identify further factors that help measure biological age more accurately. This may increase our influence over our life expectancy far more than is currently possible.