The risk for multiple sclerosis (MS) is raised by up to 30% by stressful life events according to a recent study, with women more affected than men.
The researchers said it is the largest population-based case-control study about the issue. Other work has hinted that suggested that stress-related disorders carry a greater risk of autoimmune disease, but specific ties to MS are unknown.
The findings also suggest a window of opportunity to intervene, as stressful major life events that occur 5 years or less before being diagnosed with MS seems to carry the greatest risk.
The authors used data from the Epidemiological Investigation of Multiple Sclerosis, which began in 2005 in Sweden. It includes both men and women, aged 16 to 70 years, and is a case-control study aimed at probing MS genetic and environmental risk factors.
Neurologists examined newly diagnosed cases fulfilling McDonald criteria at 42 participating hospitals. Time of disease onset was defined as the year and month when the first symptoms of MS appeared, with the year set as the index year.
For each case, controls were randomly selected from the continuously updated national population register and matched by age, sex, and residential area.
In total, 3185 people with MS and 9208 controls were invited to participate; 2930 patients and 6170 controls responded (a participation rate of 92% among individuals with MS and 67% among controls).
Using a self-administrated questionnaire, participants were asked about demographic characteristics, lifestyle, and psychosocial factors. They were also asked if they experienced any 10 life events considered stressful during the prior 10 years:
To be included in the study, the stressful event had to have happened before the onset of MS symptoms.
The life events were grouped into 4 categories, given their interrelationship with each other, and this is where the researchers found that some types of stressful events affected women more than men.
Cluster 1 contained death of a close relative or friend.
Cluster 2 contained 2 events relating to family: sickness or accident of a spouse, partner or child, or death of a spouse, partner or child.
Cluster 3 contained 3 areas related to intimate or romantic relationships: marriage, divorce, and conflict with a spouse or partner.
Cluster 4 contained 4 events relating to work or social relationships: poor economy, unemployment, conflict at work, and serious conflict with a close relative or friend.
Compared with those who reported no such situations (although the majority of the study group did) the risk of MS rose as the number of total events increased (P = .001).
Conflict at work or within families, marriage, and sickness or accidents of family members were more likely to affect women.
Most life events that happened before MS onset were significantly associated with an increased disease risk of 15% to 30%.
Jiang X, Olsson T, Hillert J, Kockum I, Alfredsson L. Stressful life events are associated with the risk of multiple sclerosis. Eur J Neurol. Published online August 2, 2020. doi:10.1111/ene.14458