ALSの疫学と発症リスク

A Brief Review on Recent Epidemiologic Literature and Risk Factors of Amyotrophic Lateral Sclerosis

ALSの最近の疫学的報告を中心に紹介した。発症率・有病率は，東アジアで低く，欧米白人で高く，日本はその中間と推定された。男女比は1.3〜1.6倍で男性に高く，加齢による増加を確認した。1997〜2015年度の本邦のALS医療受給者証所持者数を集計し，日本のALS診療ガイドライン（2013）上の，発症率1.1〜2.5，有病率7.0〜8.5（人／10万人／年）の見積りは妥当と判断された。ALS発症リスクとして喫煙が挙げられたが，他要因についてはさらなる検討が必要であった。

Abstract

This brief review of recent epidemiologic literature and risk factors of sporadic ALS found that the incidence and prevalence of the condition is higher among Caucasians and lower in East Asians, with the Japanese in the middle. The review also found that worldwide, the prevalence increases with age and the condition is 1.3 to 1.6 times higher in males than in females. The number of patients with ALS was calculated based on official diagnostic certificates from fiscal 1997 to 2015 obtained from a registry managed by Japan's Ministry of Health, Labor and Welfare. The data matched with those reported in the guidelines of the Japanese Society of Neurology (2013), with an incidence of 1.1-2.5, and prevalence 7.0-8.5/100,000 people. Smoking has been considered an established risk factor for sporadic ALS. The following possible risk factors have been speculated but are to be confirmed: excessive physical activity, head trauma, farming, environmental pollutants, pesticides, exposure to certain metals/heavy metals, electromagnetic fields, alcohol, low BMI, and low-density lipoprotein. Bandres-Ciga et al. applied linkage disequilibrium score regression and Mendelian randomization to a large data set and concluded that elevated low-density lipoprotein cholesterol is a causal risk factor for ALS.