I have never liked the class of argument, often presented whenever new biomarkers are close to realization, that suggests people should be prevented from using them because they are emotionally fragile and cannot handle the information responsibly. Ignorance wielded as shield, a sentiment that should be - but isn't - deeply offensive to all in this era of information and communication. This argument has been voiced for biomarkers for conditions without viable therapies, such as Alzheimer's disease. Here it is voiced for biomarkers of aging, a field in which there exist rejuvenation therapies, senolytics, with ample animal evidence, but that are not yet conclusively proven to produce rejuvenation in published human trials.
To me, this eagerness to forbid seems little more than control for the sake of control, a sadly widespread state of affairs in the heavily regulated medical field. There are any number of people willing to argue that medical technologies and medical information should be even more locked away behind walls and rules, even harder to obtain and use, than is presently the case. Those arguing inevitably count themselves among the enlightened few, defending the benighted and the ignorant masses from their own self-sabotaging ways. This is a form of dehumanization of the other, and it is a part of the road to truly unpleasant end stages for regional governance, as well illustrated over the course of the past century or so.
Over the past several years, scientists have identified four genetic and molecular biomarkers that potentially predict human and animal longevity. The first is the rate at which an individual's telomeres shorten in length. There is increasing evidence from both human and animal studies that the slower the rate of telomere shortening, the longer that individual is likely to live. The second is the rate of gene methylation, indicating an increased level of methylation was correlated with shortened longevity. The third is the polygenic risk. A recently reported genetic analysis can identify "10 percent of people with the most protective genes, who will live an average of five years longer than the least protected 10 percent," according to a statement from a scientist who developed the method.
The fourth approach was described in a study this year that identified 14 blood-based biomarkers of metabolism that when combined into a predictive score was statistically associated with predicting the end of life. Screening individuals using these metabolite profiles appeared to be predictive of a high risk of mortality within 10 years. In this study, scientists included more 44,000 people from 12 cohorts who were followed between three and 17 years to establish a correlation with these blood metabolites and longevity. There are no comparable studies that have examined such a large population using telomere length or gene methylation as longevity predictors.
Each of the four approaches to predicting longevity raises several scientific and ethical concerns that need to be addressed. The blood-based biomarker studies differ from current clinical end-of-life predictors, such as blood pressure and cholesterol levels, because there are established behavioral and drug interventions to reduce blood pressure and cholesterol levels. Were biomarkers to be developed for clinical applications, we propose that they should only be used if they provide actionable results. We should be cautious in applying both premature and unproven longevity results in a clinical situation that has such serious implications.
Several companies are already offering consumers tests to assay their telomere length. We would not be surprised if in the future companies will use other biological or genetic predictors to assess human longevity or offer ways to reverse our biological clocks. We also caution consumers against seeking out such longevity predictions should they be offered direct to the public, unless companies present the results to the consumer by a certified genetic counselor, as the psychological effect from these data could be devastating. Furthermore, the unintended consequences of using end-of-life predictions based on these preliminary studies can be unsettling. Do we want our life insurance agents canceling any policy or raising rates based on our biomarkers? In conclusion, we have not reached the point when it is ethical and scientifically valid to use biomarkers to predict longevity.