The telomere is the outermost part of the chromosome. With increasing age, telomeres shorten, and studies have shown that oxidative stress and inflammation accelerates this shortening. On this basis it has been suggested that telomere length is a measure of biological aging, and telomere length has subsequently been linked to age-related diseases, unhealthy lifestyle, and longevity. The research team shows that shorter telomere length is associated with both recurrent depression and cortisol levels indicative of exposure to chronic stress.
The study includes 91 patients with recurrent depression and 451 healthy controls. Telomere length, measured in white blood cells, is shorter among the patients compared with the control group. The scientists also examined the participants’ stress regulation using a so-called dexamethasone suppression test.
“The test revealed that cortisol levels indicative of chronic stress stress are associated with shorter telomeres in both depressed and healthy individuals,” says Mikael Wikgren, a doctoral candidate in the research group. The fact that depressed patients as a group have shorter telomere lengths compared to healthy individuals can be largely explained by the fact that more depressed people than healthy people have disturbed cortisol regulation, which underscores that cortisol regulation and stress play a major role in depressive disorders.
The article is part of Mikael Wikgren’s dissertation work. The research team, led by Professor Rolf Adolfsson, also includes Karl-Fredrik Norrback, Ph.D, (supervisor), doctoral candidate Martin Maripuu, and project coordinator Annelie Nordin. The study was carried out in collaboration with researchers from the Department of Medical Bioscience, Umeå University, as well as scientists at Stockholm University, Linköping University, and Antwerp University.
Wikgren M, Maripuu M, Karlsson T, Nordfjäll K, Bergdahl J, Hultdin J, Del-Favero J, Roos G, Nilsson LG, Adolfsson R, Norrback KF. Short telomeres in depression and the general population are associated with a hypocortisolemic state. Biol Psychiatry. doi:10.1016/j.biopsych.2011.09.015