Epidemio-environmental studies on amyotrophic lateral sclerosis in the Kii Peninsula of Japan : Active or disappearing focus?

在过去的三十年里，肌萎缩侧索硬化症（ALS）的频率在日本纪伊半岛和关岛稳步下降。与关岛不同的是，纪伊半岛疫源地之一的小泽川的人口从1955年至1990年大幅减少了约50%。这就提出了一个问题，是否有倾向于ALS的小泽川人已经从这个高风险地区移民，导致“焦点灭绝”。以前的流行病学环境研究（1959-1971）表明，朝南在纪伊半岛，平均年死亡率增加沿着地区河流中的钙和镁含量的减少。然而，在1985-1994年期间，这种负相关消失了，相应地，室路地区（纪伊最南端）的ALS疫源地消失了。因此，在1989-1993年期间，我们调查了和歌山县ALS患者的发病率和迁移模式，其中包括一个高发纪伊半岛疫源地（“小泽川疫源地”）。 ...更多信息 d检查焦点是否真正消失。在5年中，观察了77例ALS患者，平均发病年龄为61.8岁。总体而言，平均年发病率为每10万人1.43例（男性2.23例，女性0.71例）;按1990年日本人口调整年龄后，为1.25例（按性别分别为1.85例和0.61例）。60至69岁年龄段的平均年发病率最高，男性和女性合计的发病率最高为5.31;男性为8.88，女性为2.36。和歌山县的五个地区的比率从0.38到2.48不等。从地理上看，发病率高的地区分布在中部和最南部地区;最高的是Kozagawa重点地区，有9.54人（五年内有两例ALS病例; 1990年的基础人口为4，193人）。在研究期间，有4名来自小泽川的移民在离开焦点地区1 ~ 40年后患上了ALS。虽然ALS的显著聚集性被认为已经消失，但纪伊半岛南部仍然是ALS的高风险地区，特别是如果将数据解释为包括移民的话。一般来说，发病年龄在过去20年中从56.5岁增加到61.7岁;注意到男性占优势。少

The past thirty years, the frequency of amyotrophic lateral sclerosis (ALS) has steadily declined in the Kii Peninsula of Japan as well as Guam. Unlike Guam, the population of Kozagawa, one of the Kii Peninsula foci, has greatly decreased, by about 50%, from 1955 to 1990. It raises a question whether Kozagawa people predisposed to ALS have emigrated from this highrisk area, resulting in "focus extinction".Previous epidemio-environmental studies (1959-1971) showed that toward the south in the Kii Peninsula, average annual mortality rates increased along with a decrease of Ca and Mg contents in area rivers. However, during the period from 1985-1994, this negative correlation disappeared, corresponding to the disappearance of ALS foci in the Muro district (southernmost Kii).During the period of 1989-1993, therefore, the incidence rates and migration patterns of patients with ALS in Wakayama Prefecture, including one of the high-incidence Kii Peninsula foci ("Kozagawa focus"), were surveye … More d to examine whether the focus truly disappeared or not. During the 5 years, 77 ALS patients were observed with an average age at onset of 61.8 years. Overall, the average annual incidence rate was 1.43 per 100,000 population (2.23 for males and 0.71 for females) ; when age-adjusted to the Japanese 1990 population, it was 1.25 (1.85 and 0.61 respectively by gender). Average annual age- and sex-specific incidence rate was the highest in the 60 to 69-year range, with a peak of 5.31 for both males and females combined ; 8.88 for men and 2.36 for women. The rates varied in the five regions of Wakayama Prefecture from 0.38 to 2.48. Geographically, the areas with high incidence were distributed in the central and southernmost regions ; the highest being in the Kozagawa focus with 9.54 (two ALS cases for the five years ; 4,193 base population, 1990). During the study period, four emigrants from Kozagawa had developed ALS one to four decades after leaving the focus.Although the remarkable clustering of ALS had been thought to have disappeared, the southern Kii Peninsula remains a high-risk area for ALS,especially if one interprets the data so as to include the emigrants. In general, the age at onset has increased on the past 20 years from 56.5 to 61.7 ; and male predominance is noted. Less