Why do some people who live a healthy lifestyle still have a short lifespan? A new international study, conducted by UCLA geneticist Steve Horvath and his team of 65 scientists in seven countries, suggests our DNA is the key to the answer. The team recorded age-related changes to human DNA, calculated the biological age of blood, and estimated a person’s life expectancy. The findings suggest that early death can be predicted by examining biological age, regardless of chronological age.
The research was conducted by Steve Horvath, the principal investigator and a professor of human genetics and biostatistics at the David Geffen School of Medicine at UCLA, and 65 international scientists.
They examined 13 sets of data, which included the DNA in blood samples collected from over 13,000 people in the U.S. and Europe. The scientists measured the rates of aging of each individual using an epigenetic clock, developed by Horvath in 2013. The clock operates by calculating the aging of blood and tissues by tracking a natural process called methylation, which alters DNA over time. They then compared chronological, or actual age since birth, to the blood’s biological age to estimate the person’s life expectancy.
Brian Chen, the study’s first author and a postdoctoral fellow at the National Institute on Aging, said “Our findings show that the epigenetic clock was able to predict the lifespans of Caucasians, Hispanics and African-Americans in these cohorts, even after adjusting for traditional risk factors like age, gender, smoking, body-mass index and disease history.”
Discoveries revealed that 5% of the population’s biological rate was faster, which resulted in a shorter life expectancy. Accelerated aging in the blood increases the risk of death by 50% at any age. Researchers of the study believe this explains why some individuals die young, despite following a nutritious diet, exercising regularly, drinking very moderately, and not smoking.
“While a healthful lifestyle may help extend life expectancy, our innate aging process prevents us from cheating death forever, yet risk factors like smoking, diabetes and high blood pressure still predict mortality more strongly than one’s epigenetic aging rate,” emphasized Horvath.
The research team and co-author Dr. Douglas Kiel, a professor at Harvard Medical School, believes this DNA marker is key to discovering how to “slow the rate and maximize a person’s years of good health.”
According to the World Health Organization, the population of aging adults will continue to increase more than ever before. The high costs associated with disease and disability may pose a serious issue for many countries, therefore, “We must find interventions that prolong healthy living by five to 20 years. We don’t have time, however, to follow a person for decades to test whether a new drug works. The epigenetic clock would allow scientists to quickly evaluate the effect of anti-aging therapies in only three years,” said Horvath.
Schmidt, E., “Epigenetic clock predicts life expectancy, UCLA-led study shows,” UCLA Newsroom web site, September 28, 2016; http://newsroom.ucla.edu/releases/epigenetic-clock-predicts-life-expectancy-ucla-led-study-shows.