集団レベルでみた運動ニューロン疾患

Epidemiological aspects of motor neuron disease

　運動ニューロン疾患MNDは重大な疾患であるが，研究方法が限られており，これまでも疫学は重要な役割を演じ，頻度・実態・分布，それらの時間的・空間的変動の記述，発症要因の分析，家族集積性の評価などを通じて，本態の解明に大きな貢献をした。

　本稿ではMNDの疫学の方法論と主な知見を展望し，新しい動きにも触れる。なお，著者は本誌でおなじ展望を試み，他にも総説を著したので，基礎的事実はなるべく重複を避ける（近藤，1977，1986，1989；Kondo，1978，1994，1995）。

After briefly reviewing basic data on frequency and the familial aggregation, this paper described biometrical data on motor neuron disease (MND), particularly based on the national mortality data in Japan. Age-specific log mortality rate was linear against age (Gompertz law). A factor analysis revealed that the mortality was almost identical primary and secondary components as the overall mortality of the Japanese due to all causes, and was reverse to the components determining “industrial activity”, suggesting that traditional Japanese life contained hidden risk factors to MND.