Stressful Events Do Not Increase Risk of Multiple Sclerosis
Stress has many negative health effects on the body and an increase in the likelihood of developing an autoimmune disease such as Multiple Sclerosis was thought to be one of them. However, a new analysis of data from two large US studies, conducted by researchers at the University of Bergen in Norway, find that stressful events in fact do not increase the risk of MS.
Stress Thought to Negatively Affect Immune System, Cause Damaging Inflammation
Previous studies have suggested that stress causes and exacerbates MS through mechanisms involving the glucocorticoid and beta-adrenergic pathways in the body. Glucocorticoids are important mediators of the immune system and modulate the biological activities of inflammatory cytokines. Beta-adrenergic receptors are involved in many fundamental processes including cell growth and metabolism. A lack of these receptors have been linked to MS in mice.
Trond Riise PhD and colleagues used data from the Nurses’ Health Study and the Nurses’ Health Study II. The first was established in 1976 and enrolled 121,700 women ages 30 to 55. The focus of the study was general stress at home and at work. The second study began in 1989 and enrolled 116,671 women between the ages of 25 and 42. This study asked questions about abuse and trauma in childhood and adolescence. Diagnosis of MS was both self-reported and verified by neurologists.
After adjusting for other factors such as age, ethnicity, latitude of birth, body mass index (at age 18), and smoking, the risk of developing MS was not associated with any level of stress in the home or workplace, nor was it associated with childhood abuse.
Riise did note that a major challenge for objectively studying the relationship between stress and the development of MS is getting an unbiased measurement of stress. "A prospective design can overcome biases related to the effects of MS symptoms on self-reported stress," he wrote. "However, because the disease is infrequent, initiating a prospective study specifically with this aim is not feasible."
Multiple Sclerosis is caused by damage to the nerve’s myelin sheath due to inflammation. When this covering is damaged, nerve impulses are slowed or stopped causing symptoms such as loss of balance, muscle spasms, problems with walking, vision loss or double vision, facial pain, and numbness or tingling in arms and legs. People with a family history of MS or those who live in certain geographical areas have higher risk of developing the disease.
Riise T, et al "Stress and the risk of multiple sclerosis" Neurology 2011; 76: 1866-1871.