A new study by Stanford University scientists found that the aging process, in addition to its gradual progression, exhibits pronounced spikes at ages 44 and 60.
Over 135,000 types of molecules and microbes were examined in samples collected from more than 100 adults between the ages of 25 and 75, including blood, stool, skin samples, and nasal and oral swabs.
New samples were taken and examined every three to six months for several years—1.7 on average, with the longest monitoring period for a single participant spanning almost seven years.
“Remarkably, many molecular markers and biological pathways exhibited a nonlinear pattern throughout the aging process,” the researchers wrote.
After adjusting the test results for confounding factors such as ethnicity, BMI, sex, insulin resistance, and sensitivity, the team found that the presence of most of the molecules changes nonlinearly during aging.
The abundance of these molecules and microbes increased or decreased, depending on their specific type, rapidly around two ages: first around a person’s early 40s and again in the early 60s.
The study confirms and provides insight into the sudden increases in aging-related diseases and mortality risks after specific time points, as documented by earlier studies.
According to the Stanford researchers, observing these sudden changes in the abundance of molecules and microbes vital to our metabolism and immune system provides valuable insights into the mechanisms of the overall aging processes of the human body and associated diseases such as the ones mentioned above.
The researchers said the observed sudden changes also suggest that kidney function decreases significantly at these age thresholds.