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 said “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.