Want to Know When You're Going to Die?

There is now a test with the Nobel stamp on it that one day may answer a query that has vexed philosophers, poets, and actuaries since humans first became aware that each of us will die.

The test comes from measuring the length of a person's telomeres, a tiny structure in your cells that caps the ends of chromosomes (long stretches of DNA) to keep them from unraveling, much like the plastic tips of shoelaces. As cells replicate, these caps get shorter. Eventually, when they disappear completely, a cell dies. Enough cells kick off, and you die.

Researchers have linked shorter than average telomeres to a higher risk for diseases of aging such as cancer, heart disease, and Alzheimer's disease - and, yes, to earlier death. Research on mice has shown that lengthening telomeres can extend lives.

Scientists also have found a link between stress and shorter telomeres, and between reducing stress and slowing Telomere shrinkage. Numerous labs are experimenting with the impact of diet, supplements such as omega-3 fatty acids and exercise on keeping telomeres long.

Now comes an announcement that the Nobel Laureate responsible for co-discovering telomeres, Elizabeth Blackburn, is offering a consumer test to measure a person's telomeres. A biologist at the University of California at San Francisco, Blackburn is co-founder of Telome Health of Menlo Park, California, a company that is planning later this year to offer a $200 test to consumers that was previously available only to researchers.

"It is like a cholesterol test," said Blackburn in an interview with New Scientist. "We can take a measurement from blood samples, cheek swabs or saliva. Specifically, we measure the telomere length in white blood cells. Cells from the immune system act a bit like a report card, an indicator for all kinds of conditions."

Other telomere-auguring businesses include Houston-based SpectraCell Laboratories, which already offers a telomere test for $290. Spain-based Life Length will soon be selling what they call a more sophisticated test for 500 euros (~$700).

There are, however, plenty of questions about what telomere length really tells you. Critics of personal telomere tests include Johns Hopkins molecular biologist Carol Greider, who won the 2009 Nobel Prize with Elizabeth Blackburn. "The science really isn't there to tell us what the consequences are of your telomere length," she told the New York Times, except in a few people with specific diseases.

Telomere length also varies widely among different people of different ages, she said. "A given telomere length can be from a 20-year-old or a 70-year-old. You could send me a DNA sample and I couldn't tell you how old that person is."

Blackburn's test won't use telomeres to identify your current age, however. It will check an individual's telomere length against averages and tell you if yours are short or long, presumably according to one's age. "Checking your telomere length is a bit like weighing yourself," said Blackburn, "you get this single number which depends on a lot of factors. Telomere length gives a sense of your underlying health."

Immortal - Liz Blackburn on telomeres from RiAus on Vimeo.

Personally, I'm not sold on spending $200 on what sounds like a vague result that is unlikely to tell me something that I don't already know, such as stress is bad for me and that exercise and a healthy diet are good for me. (I would, however, be curious to take the test if it were cheaper or free!).

Still, as Blackburn offers the test to thousands of people who will undoubtedly flock to buy it, she and her team plan to refine the accuracy and utility of the test by collecting data on how it works for real people. If it turns out to be a reliable predictor of one's risk for the diseases of aging, and for aging itself, I suspect that telomere testing will become routine.

Until then, you might want to consider spending your money on a membership in a gym.