Childhood trauma may be linked to a heightened risk of multiple sclerosis in later life among women through an autoimmune mechanism, according to Norwegian research.
A study published in the Journal of Neurology Neurosurgery & Psychiatry showed that childhood sexual and emotional abuse were associated with an increased risk of developing MS independent of environmental risk factors.
The risk was higher when exposed to several abuse categories, indicating a dose–response relationship, said the authors led by Dr Karen Eid of the Department of Neurology, Haukeland University Hospital, Bergen.
The researchers drew on data from nearly 78,000 pregnant women participating in the Norwegian Mother, Father, and Child cohort study between 1999 and 2008, with follow up until the end of 2018.
Information on childhood abuse before the age of 18 was gathered through questionnaire responses, while confirmation of MS diagnoses was obtained from linked national health registry data and hospital records.
In all, 14 477 women said they had experienced childhood abuse while 63,520 said they hadn’t. The women with a history of abuse were more likely to be current or former smokers–a known risk factor for MS–to be overweight, and to have depressive symptoms.
Some 300 women were diagnosed with MS during the monitoring period, nearly 1 in 4 of whom (71;24%) said they had been abused as children compared with around 1 in 5 (14,406;19%) of those who didn’t develop MS (77,697).
After adjusting for factors including smoking, obesity, educational attainment, and household income, women who had been abused as children were significantly more likely to be diagnosed with MS.
The observed association was strongest for sexual abuse (Hazard Ratio 1.65, 95% CI 1.13 to 2.39), emotional abuse (HR 1.40, 95% CI 1.03 to 1.90) and physical abuse (HR 1.31 (95% CI 0.83 to 2.06).
The risk of MS was further increased if women were exposed to two (HR 1.66, 95% CI 1.04 to 2.67) or all three abuse categories (HR 1.93, 95% CI 1.02 to 3.67), indicating a ‘dose-response’ association, suggest the researchers.
Similar results were obtained after the researchers excluded women who might have been in the prodromal phase of MS when obvious symptoms had yet to appear.
The researchers said their study was based on previous research that showed trauma in childhood and adolescence can alter the immune system and may increase the risk of autoimmune disorders.
“Childhood abuse can cause dysregulation of the hypothalamic–pituitary–adrenal axis, lead to oxidative stress and induce a proinflammatory state decades into adulthood,” they wrote.
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, they added.
Previous research had shown that neonatal emotional and physical stress increased the susceptibility and severity of MS-like disease in mice, due to downregulation of adrenergic receptors in innate immune cells
“Better understanding of the risk factors and timing of risk exposures, may open doors for prevention and give further insight to disease mechanisms,” they concluded.