Neuroepidemiologic Research Initiatives on Guam: Past and Present

Abstract

Since the middle of this century, a remarkable concentration of cases of neurodegenerative disease(s), referred to as amyotrophic lateral sclerosis and Parkinson-dementia complex (ALS/PDC), has been recognized among Chamorro natives of Guam. Intense investigations over the last 4 decades have failed to determine the etiology of these invariably fatal diseases. Over the same time period, the incidence of ALS has decreased dramatically, the incidence of PDC has decreased, but to a lesser degree, and age at onset has shifted to a later age by about 1 decade. Almost 50% of demented patients present without the classical Parkinsonian features of PDC, and the morphological picture has changed. Results of past and present research initiatives are reviewed.

Incidence of aspiration pneumonia in ALS in Olmsted County, MN

“…Also similar is the age of onset, 62 years, and the mean survival from diagnosis, 26 months (4). Apart from a few notable geographic clusters (11,12) these demographics appear to be consistent across other studied populations (3,13).…”

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

“…The Western Pacific form of ALS, referred to as ALS and parkinsonism-dementia complex (ALS/PDC), was identified in the 1950s in three distinct geographic isolates: Guam, western New Guinea and the Kii Peninsula of Japan [14,15]. Over the past four decades, the incidence of ALS/PDC has markedly declined in Guam [14].…”

Parkinson–dementia complex and development of a new stable isotope dilution assay for BMAA detection in tissue

“…Parkinson-dementia complex (PDC) of the Chamorro on Guam and surrounding Mariana Islands is a unique neurodegenerative disease that remains a significant public health burden to the older members of this indigenous ethnic minority (Hirano et al , 1961; Waring, 1994; Murakami, 1999; Oyanagi and Wada, 1999; Wiederholt, 1999; Galasko et al , 2002). Previously, PDC was often co-morbid with amyotrophic lateral sclerosis (ALS); however, the incidence of ALS among Chamorros has returned to levels comparable to the rest of the world over the last 50 years (Garruto et al , 1985; Wiederholt, 1999; Plato et al , 2002; Waring et al , 2004).…”