Self reported stressful life events and exacerbations in multiple sclerosis: prospective study

OBJECTIVE: To study the relation between self reported stressful life events not related to multiple sclerosis and the occurrence of exacerbations in relapsing-remitting multiple sclerosis. DESIGN: Longitudinal, prospective cohort study. SETTING: Outpatient clinic of department of neurology in the Netherlands. PARTICIPANTS: Patients aged 18-55 with relapsing-remitting multiple sclerosis, who could walk with a cane or better (score of 0-6.0 on the expanded disability status scale), and had had at least two exacerbations in 24 months before inclusion in the study. Patients with other serious conditions were excluded. MAIN OUTCOME MEASURE: The risk of increased disease activity as measured by the occurrence of exacerbations after weeks with stressful events. RESULTS: Seventy out of 73 included patients (96%) reported at least one stressful event. In total, 457 stressful life events were reported that were not related to multiple sclerosis. Average follow up time was 1.4 years. Throughout the study, 134 exacerbations occurred in 56 patients and 136 infections occurred in 57 patients. Cox regression analysis with time dependent variables showed that stress was associated with a doubling of the exacerbation rate (relative risk 2.2, 95% confidence interval 1.2 to 4.0, P = 0.014) during the subsequent four weeks. Infections were associated with a threefold increase in the risk of exacerbation, but this effect was found to be independent of experienced stress. CONCLUSION: Stressful events were associated with increased exacerbations in relapsing-remitting multiple sclerosis. This association was independent of the triggering effect of infections on exacerbations of multiple sclerosis.