According to scientists, age may be more than a number. Instead, it is at least nine different numbers. Different organs or body systems are ageing at different rates according to specific biological clocks.
Is age only skin deep?
Scientists, along with septuagenarian ultramarathon runners and anyone followingCheron Twitter, have long suspected that our chronological age is a misleading measure. Since the 1960s, the notion of calculating biological age, a value that would further accurately reflect our health and lifespan.
Biomedical science has flexed the muscles of modern technology to produce estimates based on chemical alterations to our DNA or our bodies complement of RNA and proteins. However, recent advances in multiomics research, where RNA and proteins are combined for a more rigorous examination, have created a space for a much deeper dive into our biological age.
Researchers based primarily in Shenzhen in south-eastern China have revealed in unprecedented detail the complexity that drives the aging process.
Over 4,000 volunteers were recruited between the (chronological) ages of 20 and 45, revealing statistics on 403 different features, including components relating to overall health, skin characteristics, gut microbiome measurements, and 74 different measures of their metabolome.
Most human aging studies have been conducted on older people and in cohorts with a high incidence of chronic diseases. We decided to focus on this age range, according to Brian Kennedy of the National University of Singapore.
The team then split this enormous data bank into nine categories and calculated "clocks" for each one.
- Sex hormones
- Facial skin
- Physical fitness
- Gut microbiome
Some clocks tick in sync
The authors then calculated different biological age measurements for volunteers, revealing that although variation in an individual cardiovascular age was largely explained by the age on their birth certificate, it could not be said for liver age or renal age, which varies significantly between people with the same chronological age.
The researchers looked at how their different measurements correlated with each other, revealing that while most clocks ticked together, some pairs of clocks were more tightly linked than others. The result of the weak negative correlation between the rate at which the renal system is maturing, implying that a more diverse microbiome might cause the kidneys to develop harder.
The uses of biological age
The team then showed the use of their multiple clocks. The values might be used to demonstrate which component is driving an accelerated aging process in certain individuals, but some individuals may put extra pressure on different body systems, but for some that strain might impact the liver, whereas others nutrition metabolism systems.
Separate data from the National Health and Nutrition Examination Survey (NHANES) were examined to determine if age ratings for the cardiovascular, liver, and renal systems might predict mortality better than any single measure.
The researchers then looked at whether biological age measurements might improve longevity by using a data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) cohort. This dataset featured over 2,000 middle-aged people and another 2,000 centenarians. Other evidence, according to the authors, had no exceptional predictions. This is due, they believe, to the significant impacts of the environment on our bodies, which they are less likely to judge from purely biological data.
Despite the fact that the results demonstrate the unique ways in which time affects each of us and gives what the authors believe could be useful information for future healthcare. We used biomarkers that could be identified from blood and stool samples as well as some measurements from a routine body checkup.