The Effect of Childhood Viral Infections on the Incidence of Multiple Sclerosis

In this study, the history of viral infections of measles, chickenpox and mumps in childhood was compared between the two groups of adults with multiple sclerosis (MS) and healthy people. In this case-control study, a group of 45 MS patients and a group of 135 healthy people who were similar based on some variables were invited. Patients had a definite diagnosis of MS and control group consisted of people accompanying MS patients. Data were collected by a trained expert in face-to-face interview sessions. For data analysis, odds ratio index was calculated and 95% confidence interval was also computed. The mean age of respondents at the time of viral infections was also compared between the two groups. The proportions of infected people by measles, chickenpox and mumps among MS patients were 58%, 56% and 40%, respectively. These proportions in healthy group were 68%, 52% and 44%, respectively. There was not any significant difference between these proportions in the two groups. Mean age of morbidity for measles, chickenpox and mumps among patients were 6.8±3.1, 8.7±2.98 and 10.6±4.7 years, and were significantly higher that these mean ages (4.1±2.1, 5.3±3.1 and 8.4±2.8, respectively) among healthy people (p<0.001). Although there was not any significant difference between the history of morbidity of measles, chickenpox and mumps in the two groups of MS patients and healthy people, the mean ages of these viral infections among MS patients were significantly higher than healthy people.