Birth order and multiple sclerosis

Abstract

No significant difference in birth order and risk of multiple sclerosis (MS) was found in a large-scale investigation employing 2 different study methods: case-control and comparison of birth order with expected distribution. This finding is at variance with conflicting results of 2 recently published investigations. Our findings suggest that birth order cannot be used as a surrogate for age-of-infection, but must be measured directly in further studying the role of delayed childhood infection in the pathopoiesis of MS.