None of these studies have shown a causal relationship yet—in other words, we can’t say whether shortened telomeres are a cause of major diseases or just a reflection of them. For now, the only diseases clearly caused by shortened telomeres or dysfunctional telomerase are rare premature aging disorders like dyskeratosis congenita. But well-designed studies looking at telomere length and signs of health like resting heart rate have begun to provide new details concerning telomeres’ effects on biological processes, which may help us establish causality in the future. And there’s enough evidence of a connection to disease, causal or not, for folks to start wondering what their telomere length means for the future.
The most important question for people taking the telomere test, though—whether you can do anything about your shrinking telomeres, if indeed they cause disease—is the one that still needs the most research. Some studies have shown associations between telomere length and exercise, stress, diet, and smoking. For instance, one small study found that people who ate healthier diets, did yoga or meditation, and exercised daily increased the activity of telomerase, which could lead to longer telomeres. But it had no control group, which means the study needs additional confirmation. This area of research is in its infancy, and it will take many studies whose results can be compared, analyzed, averaged, replicated, and so on to make reasonable public health suggestions. How much a certain change—say, running or cutting back on fat—is going to affect your telomeres, if at all, is a level of specificity that the research can’t yet provide. As a result, the readout of your telomere length test won't come with detailed information about what to do about it.
Perhaps most importantly, the lifestyle suggestions such observational studies have pointed toward aren’t new—they’re already routinely recommended by doctors to patients. “If overweight, losing some extra weight or reducing waist circumference [may help],” says the Telome Health site. Eat less red meat; try to relax. We've heard that many times before, and presumably people are obeying that advice as much as their motivation and self-control allows, which is to say not nearly as much as we'd like. Without instructions more specific than the usual boilerplate, our telomere lengths may be more interesting, reassuring, and ominous, than actually useful.
The personal telomere test, like the personal genome test, is coming at a time when we've still got many more questions about what it will reveal than solid answers. But the test, when it arrives this fall, will certainly make it all the more pressing for these questions to be answered. And maybe people who use the test can help clarify the connection between telomeres and health: If Telome Health lets users contribute (or actively entices them to contribute) their results and detailed medical histories to science, we could all help bring the picture into better focus.