Morgan Levine, formerly Assistant Professor of Pathology and Epidemiology at Yale University’s School of Medicine and the author of the book 'True Age', is considered one of the world's leading researchers on biological aging, now working as a Principal Investigator at Altos Labs in San Diego.
In 2018, she released an ageing metric that blended multidimensional data from lab tests, designed to gauge functioning across various physiological systems.
In total, nine measures feed into the formula that combines information on physiological states from a range of different systems, including cardiovascular, immune, liver, kidney, and metabolic. This data is then collated to generate an overall biological age measure for an individual. When paired with information on your chronological age, we can estimate what we term 'phenotypic age'. The term 'phenotypic' can be defined as a characteristic of an individual that results from the interaction of their genotype with their environment. As such, we use 'phenotypic age' to refer to a characteristic ageing profile of an individual, influenced by both genetic and non-genetic factors.
The nine blood measures used to estimate phenotypic age were selected from a pool of nearly fifty potential tests. This selection process was performed using a method known as 'machine learning', where a computer is programmed to develop a mathematical prediction. In this case, Dr Levine and her team were aiming to predict remaining life expectancy. Consequently, the combination of the nine measures and chronological age represented the best predictor of life expectancy out of all the possible combinations they considered. When independently tested, phenotypic age was able to predict with approximately 90 percent accuracy who would survive the next ten years and who would not, without needing to know anything else about the individual. Clearly, they couldn't predict who would be hit by a bus or who would contract a rare yet fatal disease, but their measure was highly accurate because most people die of age-related diseases, and they were directly estimating the largest risk factor for death — biological ageing.
Let's envisage a scenario where you enter all the required information, but the biological age value displayed on your computer screen isn't quite what you had hoped for. The encouraging news is that this value can likely be altered. A high biological age shouldn't make you feel defeated, but rather it should serve as an awakening, aiding you in becoming the healthiest version of yourself. Dr Levine's lab has noticed some rather intriguing findings—chiefly, that biological age is more influenced by lifestyle factors than it is by your genes.
Her lab assessed the relative impact of various personal characteristics within an exceptionally large adult population, representative of the US population. Their groundbreaking discovery was that a person's biological ageing seemed to be most strongly influenced by their health behaviours. Recent stressors and adversities were the second largest contributors, followed by genetics in third place. While your genes and (to a certain extent) the adversities you face throughout your life are beyond your control, their study suggests the biggest influence on your ageing boils down to the lifestyle choices you make in relation to exercise, smoking, drinking, nutrition, and sleep. This revelation is promising, as these are factors that we all have control over in our lives.