Seasonal pattern of births in patients with multiple sclerosis

Abstract

The birth data of 816 patients with the diagnosis of multiple sclerosis (MS) according to the McDonald criteria referred to the University Clinic of Neurology Regensburg were assessed for annual periodicity of birth dates. All data were expressed as rates, i.e., number MS births per total number of births per month, prior to descriptive and time series analysis. A significant annual variation of birth rates was found in both genders, with the peak in birth rates per month occurring in late winter and spring months. A cosinor model indicated an acrophase (cosine-model approximation derived peak time) of birth rate in April. These results are consistent with the findings of most of the earlier studies conducted in other countries located in the Northern hemisphere that revealed an excess of MS births in the spring.