Phenotypic age is a measure of biological age that can tell you if you are physiologically younger or older than your chronological age as well as what your chances are of dying in the next 10 years. It has long been appreciated that chronological age by itself is a very potent predictor of mortality risk. This is the basis of the actuarial tables used in life insurance to determine premiums. Health habits such as exercise, smoking, and risk behaviors can be added to these actuarial tables to improve risk stratification. However, it is also well known that poor health habits do not affect all individuals in the same way. Therefore, looking for biomarkers of organ system functioning directly, i.e., measuring how the sum of the healthy and risky behaviors as well as genetic background are affecting a particular individual, is a more powerful way to assess the effectiveness of therapies and lifestyle changes on biological age and risk of death.
Morgan Levine, PhD and her team took this approach and analyzed data from the National Health and Nutrition Survey III using machine learning algorithms to improve upon chronological age by adding 9 biomarkers found in routine blood tests in over 9,926 subjects. These subjects were followed for up to 23 years to see who had died or developed cardiovascular disease, cancer, dementia, diabetes, etc. They found that their algorithm correlated highly with chronological age (r=0.9) but also predicted all-cause mortality and death from specific diseases better than chronological age alone.
In addition to age, the following nine blood tests are used to calculate Phenotypic age: albumin, creatinine, glucose, c-reactive protein, lymphocyte percent Immune, mean cell volume (MCV), red cell distribution width (RDW), alkaline phosphatase, and white blood cell count. M. Levine, et. al. An epigenetic biomarker of aging for lifespan and healthspan
The scatterplot below compares the biological PhenoAges of patients in the PhysioAge database (black line) with the National Health and Nutrition Examination Survey (NHANES) population (red line), a reference pool often used in health sciences research. On average, patients in these age management practices are biologically 5-10 years younger with respect to PhenoAge than their chronological age-matched NHANES counterparts.