Some people are destined to age faster and die younger, regardless of how they treat their bodies, according to a major analysis of biological ageing.
American researchers found that the 5% of the population which is predisposed to ageing fastest is 50% more likely to die at any age than everyone else.
Steve Horvath, principal investigator and a professor of human genetics and biostatistics at UCLA said in a statement:
“While a healthful lifestyle may help extend life expectancy, our innate ageing process prevents us from cheating death forever.”
But he added that while our internal clock affects mortality, risk factors like smoking, diabetes and high blood pressure are still more significant.
Horvath’s team predicted life expectancies by tracking methylation – a process that chemically alters DNA over time.
The study offers the strongest evidence yet that methylation leads to faster ageing and earlier death, paving the way for treatments to slow down the process.
Dr Douglas Kiel, a professor at Harvard Medical School and co-author of the study, said in a statement:
“This study validates the use of DNA methylation as a biomarker for biological age. And if we can prove that DNA methylation accelerates ageing, we can devise strategies to slow the rate and maximise a person’s years of good health.”
However, the study leaves several questions unanswered, including how the so-called epigenetic changes to DNA are exactly linked to the risk of death.
Co-author Dr Themistocles Assimes, an assistant professor of cardiovascular medicine at Stanford University School of Medicine, said in a statement:
“Do the epigenetic changes associated with chronological ageing directly cause death in older people? Perhaps they merely enhance the development of certain diseases ― or cripple one’s ability to resist the progression of disease after it has taken root.”
Assimes added that larger studies into cases of well-documented causes of death will help answer some of these questions.
The World Health Organisation has calculated that the number of people worldwide over the age of 65 will outnumber those younger than five for the first time.
The researchers said the epigenetic clock, which the university is seeking to patent, would enable medics to evaluate anti-ageing therapies over three years.