Certain people will age quicker and die sooner, even if they keep their body healthy, suggests a largescale analysis by UCLA scientists. Regardless of how well you take care of yourself, an accelerated internal epigenetic clock may lead to an earlier death for some.
Researchers assessed data from over 13,000 individuals, measuring levels of DNA methylation in hundreds of specific areas on the genome to determine their “epigenetic age.” Epigenetic marks found on DNA and histone proteins are known to impact gene expression without changing the underlying gene sequence. Horvath’s epigenetic clock can estimate the age of most tissues and cell types by tracking DNA methylation, an epigenetic modification that can selectively switch off genes.
The group’s findings, published in Aging, showed that the epigenetic clock can actually predict when someone will die more accurately than their actual age, even after known risk factors are accounted for, such as smoking, BMI, and disease history.
“Our research reveals valuable clues into what causes human aging, marking a first step toward developing targeted methods to slow the process,” said Steve Horvath, Ph.D., Professor of Human Genetics & Biostatistics at UCLA who led the international team of 65 scientists.
They found that a portion of the population – about 5 percent – ages faster than normal and, ultimately, lives a shorter life. “Accelerated aging increases these adults’ risk of death by 50 percent at any age,” noted Horvath.
In a hypothetical example, let’s imagine there are two 60-year-old men who smoke because of stress. One man’s epigenetic aging rate is considered accelerated and ranks in the top 5 percent, while the other’s is average. The chance that the first man will die within the next 10 years is 75 percent, compared to the second man whose chance is 60 percent.
In addition, the team’s research lends some truth to the old adage that the good die young. Regardless of a healthy and fit lifestyle, some people are still on the fast-track to death because their epigenetic clock seems to tick faster than normal.
“You get people who are vegan, sleep 10 hours a day, have a low-stress job, and still end up dying young,” said Horvath.
However, Dr. Themistocles Assimes, coauthor and Assistant Professor of Cardiovascular Medicine at Stanford University School of Medicine, cautioned that we still do not know the precise role of epigenetics in death and aging. “Do the epigenetic changes associated with chronological aging directly cause death in older people?” questioned Assimes. “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. Future research is needed to address these questions.”
Larger studies that use only well-documented causes of death will allow researchers to get closer to understanding the connection between specific diseases and epigenetic age, Assimes added.
Keeping pace with the growing population of the elderly and the high costs associated with diseases and disability will be difficult. For the first time ever, the number of people over the age of 65 will soon outnumber children younger than 5, according to the World Health Organization. Tracking a person for decades to test the efficacy of a novel anti-aging drug is just not feasible and would take too much time, making the epigenetic clock a viable option for assessing whether an anti-aging drug will work. “The epigenetic clock would allow scientists to quickly evaluate the effect of anti-aging therapies in only three years,” Horvath said.
Interestingly, Horvath also recently discovered that certain ethnic groups can epigenetically age slower than other groups and that menopause and insomnia might epigenetically speed up aging. Yet another study found that someone’s age could influence whether they reap the epigenetic benefits of exercising. With the world population rapidly aging, deciphering the many links researchers have found between epigenetics and age will become even more crucial.
If you’ve had your DNA sequenced, you can follow Horvath’s DNA methylation age tutorial to calculate your epigenetic age!
Source: Horvath et al. (2016). DNA methylation-based measures of biological age: meta-analysis predicting time to death. Aging, 8(9): 1844-1865.
Reference: UCLA. Epigenetic clock predicts life expectancy, UCLA-led study shows. UCLA Newsroom. 28 Sep 2016. Web.