New research from the US suggests that trauma in childhood such as experiencing abuse or a serious stressful event like losing a parent is linked to a shorter lifespan and weaker immune system later in life, and that the immune impairment even adds to that caused by the stress of caring for a family member with dementia.

The study was the work of Dr Janice Kiecolt-Glaser, professor of psychology and psychiatry, and Dr Ronald Glaser, director of the Institute of Behavioral Medicine Research, both at Ohio State University, and colleagues. The findings were presented on Saturday at the 118th Annual Convention of the American Psychological Association in San Diego, California.

Kiecolt-Glaser told the press that:

“What happens in childhood really matters when it comes to your immune response in the latter part of your life.”

The study which was partly funded by the National Institute on Aging, found that for some people, the long term effect of experiencing serious abuse or very stressful events as kids can be a shortening of life by up to 15 years.

The researchers examined blood samples and survey data given by 132 healthy older adults of average age 70 years, of which 58 (44 per cent) were the primary caregiver of a spouse or parent with dementia, and 74 (56 per cent) were demographically matched controls with no caregiving responsibilities (non-caregivers).

From the blood samples they were able to assess the levels of two stress markers: the cytokines interleukin-6 (IL-6) and tumor necrosis factor (TNF). They were also able to measure the lengths of telomeres, the bits of DNA on the ends of chromosomes that have been likened to the tape glued onto the ends of shoelaces that stop them fraying.

Shortened telomeres have been linked to aging, age-related diseases, and shorter lifespan in older people. Glaser, who is also a professor of molecular virology, immunology and medical genetics at Ohio State, explained that:

“Every time a cell divides, it loses a little bit of its DNA at the ends.”

“So the faster that process takes place, the more DNA is lost, and that’s significant,” he added.

Thus the more the telomeres “fray” at the ends of the DNA strands, the less able they are to protect the choromosomes.

From the survey data the researchers could assess the extent to which participants had experienced abuse or neglect as a child, and whether they had experienced any serious stressful events such as the loss of a parent, serious marital difficulties between their parents, or any mental illness or alcoholism in the family as they grew up.

The survey data also gave the researchers information on other factors such as level of any depression, health status and health behaviors.

The results showed that:

  • Nearly one third of participants reported experiencing some form of physical, emotional or sexual abuse as a child.

  • Those who reported being abused or having experienced serious stressful events in childhood had higher levels of IL-6 than those who did not.

  • Of these, the caregivers had higher levels of IL-6 than non-caregivers.

  • Caregivers who reported being abused as children showed the highest levels of TNF (ie more than than caregivers who did not report being abused as children, and non-caregivers, whether they reported being abused or not).

  • In contrast, participants who reported experiencing serious stressful events in childhood showed no significant increase in TNF.

  • As might be expected, participants who reported being abused in childhood showed higher levels of depression that those who did not.

  • However, those who reported serious stressful events showed no significantly higher levels of depression.

  • The telomeres of participants who reported experiencing two or more serious stressful events in childhood were significantly shorter than those of participants who did not.

  • Caregivers also showed significantly shorter telomeres than non-caregivers.

Kiecolt-Glaser and colleagues said these findings show that:

“Differences may be measurable in older adults, and of sufficient magnitude to be discernible even beyond the effects of a notably chronic stressor – dementia caregiving.”

The team had already shown in earlier studies that caregivers suffer higher rates of depression and poorer health than non-caregivers, and they also have a higher rate of mortality.

They have also discovered that caregivers suffer from a range of other ill effects: their wounds heal less quickly, their response to flu and pneumonia vaccines is poorer and they suffer more inflammation, compared to non-caregivers.

The fact the study shows these highly stressful exposures in childhood weakened the immune response even more than caregiving does, is very significant, said the researchers. We already know that inflammation due to higher levels of IL-6 and TNF are linked with cardiovascular diseases, arthritis, type 2 diabetes, cancer, Alzheimer’s disease, osteoporosis, and other diseases, they added.

Kiecolt-Glaser commented that:

“Childhood adversity casts a very long shadow.”

She said this study adds to mounting evidence that psychological factors may influence the incidence and progression of many age-related diseases via their effect on the immune system. Exercise, yoga, meditation and psychological treatment can reduce negative emotions which in turn lessen inflammation from happening in the first place, she added.

“How stress kills: Assessing the damage and various remedies.”
Janice K. Kiecolt-Glaser, Jean-Philippe Gouin, Nan-Ping Weng, William B. Malarkey, David Q. Beversdorf, Ronald Glaser.
Invited address at Session 3345, Saturday 14 August 2010, Annual Convention of the American Psychological Association, San Diego Convention Center, California.

Source: Ohio State University, APA.

Written by: Catharine Paddock, PhD