Epidemiology of motor neuron disease in the Kii Peninsula of Japan, 1989–1993: Active or disappearing focus?

Temporal trends and geographic clusters of mortality from amyotrophic lateral sclerosis in Japan, 1995–2004

“…In the Kii Peninsula, a cluster (A3) was observed but it did not reach statistical significance at the SMCZ level. Recent epidemiological surveys reported a continuing high incidence and prevalence in the subfoci of Hohara and Kozagawa villages of the Kii Peninsula [16,17,36]. Our cluster analysis may not be able to detect clustering in the two villages, which are much smaller units of area than SMCZ.…”

“…According to a 10-year prospective population-based study conducted in Italy, mean onset age (SD) has become slightly higher: 64.2 (11.2) years in 1995-1999 and 65.4 (11.1) years in 2000-2004 [27]. Although the data are cross-sectional in Japan, there is a substantial difference in age at onset between 61.8 (12.2) years in 1989-1999 [17] and 65.4 (10.7) years in 2003-2006 [28]. As another hypothetical explanation, it may be that survival duration has been prolonged by the improvement of treatment such as pharmacotherapy (e.g., rilusole) combined with nutritional and respiratory support [1].…”

“…Over the past four decades, the incidence of ALS/PDC has markedly declined in Guam [14]. On the other hand, a continuing high prevalence and incidence in Hohara in Mie prefecture [16] and Kozagawa in Wakayama prefecture [17] in the Kii peninsula are reported, although they temporarily declined in the 1980s.…”

Epidemiology and Medical Expenses of Motor Neuron Diseases in Taiwan

“…Aside from cluster areas of MND in the Kii peninsula of Japan and Guam [8][9][10][11] , only a few epidemiological studies of MND have been carried out in Asia [12][13][14][15] . The average incidence of MND was 0.31 per 100,000/year in Hong Kong Chinese between 1989 and 1992 [13] and 160 increased to 0.60 per 100,000/year during 1997-2002 [12] .…”

Survival rate of patients with amyotrophic lateral sclerosis in Wakayama Prefecture, Japan, 1966 to 2005

“…In the southern part of Kii peninsula in Japan, as well as in Guam, the incidence and prevalence of ALS in the 1960s were 100-to 150-fold higher than in other countries [2,3], and characteristics of the clinical features of Kii ALS were reported to be young onset, long clinical duration and limb onset [3]. In the analysis of the clinical features of Kii ALS, the high frequency of young onset, long survival and frequent limb onset cases was prominent [3][4][5]; however, over the last 40 years of follow-up studies in Kii peninsula foci (Kozagawa in Wakayama Prefecture and Hobara in Mie Prefecture), as well as in Guam [6], a marked decline in the incidence of ALS has been demonstrated [7]. Environmental or socioeconomic changes over the last 40 years are speculated to have played important roles in the clinical features of ALS and also in the decline in the incidence of ALS in Kii peninsula [4,7,8].…”