Younger generations are aging faster at the biological level than people born a decade or two earlier, and researchers say that gap may help explain a rise in cancers among adults under 50.
A new study from Washington University School of Medicine in St. Louis, reported by Healthline, examined biological age markers in more than 150,000 adults from the UK Biobank and more than 10,000 adults from the United States All of Us research program. The researchers compared people born in the early 1950s to those born in the late 1960s and early 1970s, and also compared people born in the 1960s to those born in the 1990s.
Their primary metric was PhenoAge, a measure of biological aging based on chronological age and nine blood biomarkers. From that, researchers calculated an age gap score to estimate whether a person appeared biologically older or younger than expected for their actual age.
People born in the United Kingdom between 1965 and 1974 showed a measurably older biological profile than the generation before them at the same chronological age. The pattern held in the American data as well.
Ketan Thanki, MD, a colorectal surgeon at MemorialCare Todd Cancer Institute in California who was not involved in the study, said the findings added meaningful information to an ongoing conversation. "The study shows that using established markers of biological age, we have evidence that younger generations are aging faster than previous generations," he told Healthline. "The study doesn't pinpoint exactly why but points toward factors that research has been suggesting for years," Thanki told Healthline.
The researchers explained the cancer connection through the biology of DNA damage. Cancer can develop when genetic damage accumulates in cells over time. When DNA is damaged, it can transmit flawed instructions, leading to malfunctions in cell division. That process is most commonly associated with aging, which is why cancer rates historically rise with age. If younger people are biologically older than expected, their cells may be accumulating that damage earlier.
The study pointed to several likely contributing factors, including obesity and metabolic dysfunction, unhealthy diet, prolonged sedentary time, circadian disruption, and exposure to environmental chemicals. However, the researchers were careful to note that more work is needed before any single cause can be identified.
"A better understanding of how generational differences in accelerated aging relate to early onset cancers is needed urgently," the study authors wrote. "This question is central because early onset cancers show strong birth-cohort effects, with more recent generations experiencing higher risk as they age," they continued.
The researchers called for follow-up studies to determine the specific mechanisms driving faster biological aging in recent generations and to clarify how that aging connects to specific cancer types appearing earlier in life.
