In a study of more than 2,400 Dutch subjects, researchers examined chromosomes within cells. What they found was surprising — people with clinical depression had shorter telomeres than their healthy peers.
Telomeres are strands of protective DNA that are found at the tips of chromosomes. As we age and our cells divide, telomeres get a little bit shorter each time. When they become so small that they lose their protective benefits, the cell dies. The more cells die, the quicker we age.
The length of telomeres is measured in terms of their number of DNA building blocks, called base pairs (bp). Shortened telomeres have been linked to a wide variety of health problems, including obesity, heart disease, diabetes, certain types of cancer and mental decline.
Study participants ranged in age from 18 to 65. The researchers found that with each year of age, telomeres shortened by 14 bp, on average, which is comparable to previous research findings.
The new study found that the telomeres in healthy people were about 5,540 bp on average, whereas in people with depression, their telomeres measured only about 5,460 bp — a significant difference.
Researchers said that based on telomere length, subjects in the study who suffered clinical depression for a period of two or more years actually aged seven to 10 years, when compared to non-depressed people.
“The most severely and chronically depressed patients had the shortest telomeres,” said lead author Josine Verhoeven, a psychiatric researcher at the Free University and Amsterdam’s VU University Medical Center.
“Overall, this study provides convincing evidence for the suggestion than an emotional stressful condition, such as [clinical depression], may truly impact on the physical ‘wear and tear’ of a person’s body resulting in accelerated biological aging,” wrote Verhoeven and colleagues.
The researchers said that while their data showed an association between depression and shorter telomere length, it could not demonstrate a clear cause-and-effect relationship. It is possible that some other factor, such as a genetic vulnerability, underlies both, the researchers said.
The study was published in the journal Molecular Psychiatry.
Source: VU University Medical Center