Researchers at the San Francisco VA Medical Center and the University of California, San Francisco, collected DNA samples from 43 adults with PTSD and 47 matched controls without PTSD.
Lead author Aoife O'Donovan say the initial analysis showed that on average, the subjects with PTSD had shorter telomere length than those without. Telomeres are DNA-protein complexes that cap the ends of chromosomes and protect them from damage and mutations. Short telomere length is associated with an increased risk of cancer, cardiovascular disease and autoimmune and neurodegenerative diseases, as well as early death.
"This was striking to us, because the subjects were relatively young, with an average age of 30, and in good physical health," O'Donovan says in a statement. "Telomere length was significantly shorter than we might expect in such a group."
The authors looked at incidence of severe childhood trauma, including neglect, family violence, physical abuse and sexual abuse, and found that, among the subjects with PTSD, the more childhood trauma a subject had experienced, the higher the risk of shorter telomere length.
"People who had multiple categories of childhood traumas had the shortest telomere length," O'Donovan says. "In contrast, subjects with PTSD but without childhood trauma had telomere length equal to those of the matched healthy subjects."
The findings are published in Biological Psychiatry.