Month of Birth Does Not Seem to Interfere with the Development of Multiple Sclerosis Later in Life in Brazilian Patients

Abstract

MS were born at the end of the winter season. In other studies, the season of birth did not seem to interfere with the development of MS later in life, despite severe winters [10] . The present study aimed to assess whether the month of birth might influence the development of MS in a specific geographic region of Brazil. The study was approved by the institutions participating in data collection. Information on the month of birth from 2,030 MS patients was obtained from Brazilian MS units in 15 cities between the latitudes of 18°55 23 S and 29°43 23 S. The typical climate of the region within these latitudes is tropical and subtropical, with mild winters and hot summers. A control group of nonneurological patients and employees from different hospital units was created with 2,030 individuals. The month of birth of MS cases and control individuals is shown in figure 1 a and showed no significant differences when compared using  2 analysis. Similarly, no differences were observed when the data set was divided into the annual seasons ( fig. 1 b). Our results are similar to those of Givon et al. [1] . Israel and Brazil share similar daylight and temperatures throughout the year. These findings may indeed reinforce the idea that stable weather without severe and dark winters might exclude the seasonal distribution of MS patients born in different periods of the year.