Evidence for Aging Clocks to Progress Faster Now than in the Past
Degenerative aging, as one might expect, is largely studied in the old. Aging happens in younger people, but doesn't kill or greatly inconvenience them, and is thus not a high priority for the research community. Thus far less is known of how exactly aging proceeds in younger adults, such as which mechanisms are more important. So it is always interesting to see researchers attempting to make some inroads into what is happening to younger adults as a result of those mechanisms of aging. Here, researchers present evidence for measures aging provided by aging clocks in younger adults to have accelerated since the 1950s; one might immediately think of the rising prevalence of obesity as the first place to look for a cause, but there are any number of other possible candidates.
Researchers analyzed data from more than 154,000 young adults in the UK Biobank, a large biomedical dataset containing biological, health and lifestyle data, and from more than 10,000 individuals in the U.S. participating in the National Institutes of Health's (NIH) All of Us Research Program, an effort to build a comprehensive health dataset on more than 1 million people living in the U.S. To estimate the level of biological aging - or age gap - the researchers examined aging at two levels: across the body as a whole, known as systemic aging, and within individual organs, known as organ-specific aging.
For systemic aging, the researchers used established measures, including clinical biomarker-based measures such as PhenoAge and the Klemera-Doubal Method, as well as a metabolomic age score, which provides a measure of individual metabolism. For organ-specific aging, the researchers used blood proteomic data, which measure levels of multiple proteins linked to specific organ systems, to estimate biological aging in individual organs.
The researchers found that individuals in the UK born between 1965 and 1974 had systemic aging that was 23% of one standard deviation higher compared with those born between 1950 and 1954, after accounting for chronological age. In other words, people in the younger birth cohort showed a modest shift toward older biological profiles than people in the older birth cohort when at the same chronological age. The researchers observed a similar pattern in the U.S cohort. Participants born between 1990 and 1999 had systemic aging that was 92% of one standard deviation higher compared with those born between 1965 and 1969.