Scientists are beginning to build consensus on the idea that exercise helps reduce aging and can even make cells in older people look and behave more youthfully under the microscope. However, the role cell aging plays in health may have just gotten more important than ever. An Austrian study on telomeres and cell aging seems to suggest that cells which appear older are also at greater risk of developing cancer.

Telomeres are pieces of protein and are part of the chromosomal structure of most cells, including human cells. They act as "caps" to the ends of chromosomal chains. These "caps" generally keep the chromosome structure stable and help reduce mutation and dissociation (the kind associated with aging and free radical or oxidative damage) that causes genetic maladies like cancer. As a cell ages and divides (a process that involves making genetic copies of the telomere-containing chromosomes), telomeres grow shorter and shorter, making the chromosomes they "cap," more vulnerable.

Peter Willeit, M.D., and university colleagues of Innsbruck Medical University, in Austria, attempted to quantify the association between leukocyte telomere length and risk of both new-onset cancer and cancer death.

From the study's public release:

Telomeres are a structure at the end of a chromosome involved in the replication and stability of the chromosome. Genetic factors and environmental stressors can shorten the length of the telomere, and telomere length has been considered to be an emerging marker of biological age. Some research has suggested that short telomeres and chromosomal instability contribute to malignant cell transformation. "Proof of concept for this intriguing hypothesis remains to be established from an epidemiological perspective," the authors write.

Although the causation relationship between telomere reduction and its possible end product, cancer, is still under investigation, Willeit and team seem confident in their hypothesis.

Short telomere length was also associated with a higher rate of death from cancer. "Of note, telomere length was preferentially associated with individual cancers characterized by a high fatality rate such as gastric, lung, and ovarian cancer, but less so with tumors linked to better prognosis," the authors write. They add that telomere length had a similar predictive value for cancer in both men and women and in various age groups.

A variety of experimental and genetic studies support the hypothesis that telomere attrition contributes to the manifestation and dissemination of malignancies. While fully functional telomeres confer protection of the genome, shortened telomeres facilitate chromosomal instability," the researchers write.

 

The study appears in the Journal of the American Medical Association (JAMA) 2010;304[1]:69-75. Read the abstract and summary of results here.