Elaine Chin, the chief medical officer of the centre, says about 30 of her clients have asked for a telomere test since she began offering it this year.
She stresses its value as a spur to behaviour modification. It’s one thing to step on a scale and find out that being overweight is a risk factor for cardiovascular disease and diabetes. It’s somehow a bit more jarring to put your DNA under the microscope and witness how your particular mode of living is playing out at a molecular level.
“People will not change their behaviour until they know they own a problem,” Dr. Chin says.
Knowing whether or not I own a problem means rolling up my sleeve and giving up some blood – lots, in fact, 14 vials in all. The reason for the big draw, Dr. Chin explains, is that the centre is not promoting telomere testing in isolation but as part of a big picture health assessment that includes looking at a wide range of nutrients and other factors in my blood.
This makes me skeptical about whether knowing my telomere length is going to tell me anything truly meaningful apart from the common sense health message about eating right and exercising more. Yet, I’m also apprehensive that it will tell me something I really don’t want to know.
What comforts me, paradoxically, is that despite media reports, telomeres do not actually tell you how long you are going to live. That’s because there’s a huge variation between individuals. A teenager can have shorter telomeres than a 70-year-old, yet that teenager is far more likely to still be around in 20 years. The correlation between telomere length and lifespan is something that emerges when larger numbers of individuals are analyzed as a group.
“It’s not a crystal ball; it’s statistical,” said Dr. Blackburn at a recent appearance in Toronto organized by the Executive Health Centre.
What’s more significant for individuals, proponents of the testing stress, is the rate of change in the length of our telomeres. That can be monitored year after year and used as an incentive to promote changes to diet and other habits.
Telomere length can also tell us about our risk of certain diseases. Short telomeres appear to correlate with higher risks for cancer, diabetes and cardiovascular disease. With telomere testing, individuals who come up short could be warned to take preventive steps, or to treat other risk factors such as stress and depression which may work in tandem with telomeres to shorten lifespan. For those who are already battling disease, the information could help guide treatment.
“Already in certain settings you can see that people who have short telomeres are responding poorly to certain drugs,” Dr. Blackburn said.
As the population ages in much of the world, individuals and as well as nations face huge burdens associated with chronic disease. Any reliable indicator that can help reduce those burdens may be just what overtaxed health-care systems need most in the coming decades.
In that broader sense, telomeres are part of a larger move toward personalized (and preventive) medicine propelled by the increasing affordability of reading and interpreting human DNA. What is today the exclusive province of private clinics such as the Executive Health Centre may be the future of public health.
There is a catch
If most of human history can be characterized by its lack of information about individual health and the risk of disease, it’s also the case that for people living in the developed world today it’s possible to have the opposite problem. There are so many different kinds of diagnostic tests available it’s become a meaningful question to ask just how much information is relevant to maintaining health, and how much is simply worrisome noise.
With the field still trying to figure out exactly how telomeres relate to aging and health, some researchers express strong reservations about telomere testing for health assessment – and taking tests at face value.
“It’s easy to get correlations in aging, because many, many things are affected as you get older,” says David Harrison, a gerontologist at the Jackson Laboratory in Bar Harbor, Me. While he doesn’t rule out that telomeres play a role in aging, he is not persuaded that their role is clear or that telomere testing is meaningful. And he is wary, he says, when researchers in the field have a commercial interest in the testing technology.
Peter Lansdorp, a professor of medicine at the University of British Columbia and scientific director of the European Research Institute for the Biology of Ageing in the Netherlands, is also cautious about individual testing. He argues that the variation in telomere tests – the degree to which the same test performed on the same sample would lead to a different result – is still too high for a single test to be very meaningful.