What is the oldest a person can be? If all extraneous factors are removed from the equation, where you let nature fully take its course and the human body is pushed to the absolute edge, how old could a person theoretically get? Researchers from Singapore believe they have the answer.
In a new study published to Nature Communications, researchers have devised a clever strategy using blood tests that they claim measures the absolute age a human body can reach. According to their indicator, called the dynamic organism state indicator (DOSI), they believe the human body has a maximum lifespan of 150 years old.
To do so, the authors combined a number of age-related variables and aging trajectories into a single metric that allowed for a simplified, quantitative maximum lifespan to be generated. Aging involves a progressive decline in function and renders the body vulnerable to the onset of disease, whether that be cancer, neurological disease, or heart conditions. Aging occurs as our DNA replicates over and over, becoming more prone to error and resultant disease.
One of our best metrics of overall health currently is a complete blood count (CBC). Delving into a variety of disorders to test for whilst analyzing the number of white blood cells, red blood cells, and platelets within a patient’s blood, a CBC can be invaluable for disease screening. By tracking CBC scores over an aging trajectory looking through patient records, the researchers discovered that variations in CBC could be utilized in creating an overall indicator of aging. This indicator represents a measurement of physical resilience, and in the study subjects, the DOSI was elevated in people with morbidity-increasing lifestyles, such as smoking. Elevated DOSI was significantly correlated with incidence of common health conditions and age, suggesting it is a strong marker of the progression of the human body.
When the researchers looked at healthy individuals, the DOSI predicted the incidence of future age-related diseases despite showing no obvious signs of disease onset at the time.
To utilize their indicator to produce a maximum lifespan, the researchers looked to the future of their study subjects. Plotting the DOSI as it linearly increased with age, the researchers were able to follow the correlation and extrapolate a maximum lifespan. They found that the progressive loss of function indicated that humans reach their full age potential at 120-150 years old, which is in line with previous research.
Interestingly, their results suggest that even with the most advanced disease-fighting therapies available to us in the future, humans would not push past this mark without solving the underlying aging issue. Loss of resilience within the body appears to be a far greater driving force of mortality than specific disease, and they state that work into developing the aging model is imperative for life-extending therapies, instead of targeting disease.