Inside every cell, there are tiny chemical tags on DNA. They are invisible to the eye, but they can tell you how worn out the body is. These tags work like a clock that runs differently for everyone: faster for some, slower for others. In people with HIV, this clock often runs ahead, which means the body ages from within faster than it should for its age.
In Tokyo, doctors are recruiting 100 men with HIV who have been on treatment for more than a year. They will take blood samples and calculate how fast their inner clock is ticking. Then they will compare this with the medications they take, how long they have been treated, whether they smoke, whether they exercise, and what they eat. This way, they can figure out what exactly makes the clock run fast and what helps it keep steady time.
Scientists hope that long-term treatment and the right habits will help slow the inner clock. If this is confirmed, doctors will be able to choose medications that age the body less and advise people with HIV on how to stay healthy longer.
The Horvath epigenetic clock, created in 2013, can predict chronological age with an error of only about 3.6 years from a sample of almost any tissue, including blood, brain, and skin.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.