As research into complex human diseases improves, a new field has emerged highlighting the massive impact trauma (and the extreme stress associated with it) can have on human health later in life.
Now, a large study on women has found that childhood trauma may increase the risk of developing multiple sclerosis later in life. The work, which is published in the Journal of Neurology Neurosurgery & Psychiatry, shows the effects of trauma can last a lifetime, and contribute to a chronic autoimmune disorder in a way that was previously unknown.
Multiple sclerosis (MS), an autoimmune disorder that affects the brain and nervous system, is an extremely complex disorder. Known risk factors other than genetic predispositions include vitamin D deficiency, Epstein-Barr virus infection, and obesity, and researchers have previously identified a critical period in childhood in which risk factors seem to have the largest impact.
Following research suggesting life stressors, such as divorce or personal conflict, have an impact on the onset of MS, a collaboration of researchers from Norway sought to explore whether childhood stressors may also increase the risk of MS by doing a prospective cohort study. Taking around 78,000 Norwegian women, 14,500 of whom were exposed to serious childhood abuse and 63,500 who were not, the researchers looked for links between emotional and physical abuse and the development of MS.
Out of the entire cohort, 300 women developed MS by the follow-up appointment. Of these 300, 71 (24 percent) reported a history of childhood abuse. Of the women that did not develop MS, 19 percent reported a history of childhood abuse, suggesting a larger percentage of abuse victims in the MS group.
The results suggest there may be an increased risk of developing MS after experiencing either sexual, emotional, or physical abuse during childhood. The risk is then further increased risk when individuals are exposed to more than one form of abuse.
This is the first study that has identified a link between MS and childhood trauma, building upon previous work that found links to trauma events that happened only a few years before diagnosis.
While the study does account for multiple risk factors, it does admit that residual confounding variables could play a role. Variables such as childhood diet, nutrition, and parental smoking could all increase the risk, though it is unlikely to account for the outcomes. There is also the question of what trauma the children experienced – while the study accounted for a few categories of trauma, there is no information on the extent of the abuse, the age at which it happened, or whether they were supported following the events.
Instead, the team believe there are underlying biological mechanisms at work. Extreme stress induced by trauma can impact a number of processes within the body and lead to inflammation, causing damage late into adult life.
“Childhood abuse can cause dysregulation of the hypothalamic–pituitary–adrenal axis, lead to oxidative stress and induce a proinflammatory state decades into adulthood,” write the authors.
“Psychological stress has been shown to disrupt the blood–brain barrier and cause epigenetic changes that may increase the risk of neurodegenerative disorders, including MS.”
The researchers now hope future studies can identify the biological mechanisms underpinning trauma interactions.