Isager H, Andersen E, Hyllested K
Acta Neurol Scand. 1980 Jun;61(6):393-6. doi: 10.1111/j.1600-0404.1980.tb01509.x.
The aim of this study was to ascertain whether there is an association between risk of multiple sclerosis (MS) and birth order position. Our reference population was 198,000 persons born in the period 1930-50 and recorded in the register of school health records from the school health service of the Copenhagen council. We compared 46 persons from the register who had developed MS with matched controls from the register, three for each case. An inverse association between risk of MS and birth order position was found. Early birth orders tend to delay exposure to an infectous agent from early childhood to a later age. Therefore, our finding supports the hypothesis that MS is causally related to an infection that is inapparent when it occurs in early childhood, while infection later in life may result in severe disease
本研究的目的是确定多发性硬化症（MS）风险与出生顺序之间是否存在关联。我们的参考人群是1930年至1950年期间出生并记录在哥本哈根市议会学校卫生服务处学校健康记录登记簿中的19.8万人。我们将登记簿中46名患多发性硬化症的人与登记簿中匹配的对照组进行了比较，每个病例对应三个对照组。研究发现多发性硬化症风险与出生顺序之间存在负相关。较早的出生顺序往往会将接触传染源的时间从幼儿期推迟到较晚年龄。因此，我们的研究结果支持这样一种假设，即多发性硬化症与幼儿期发生时不明显的感染存在因果关系，而生命后期的感染可能导致严重疾病。
