A Cohort Study of Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia on Guam and Rota

Abstract

A prospective study of the incidence of new cases of amyotrophic lateral sclerosis and parkinsonism-dementia was conducted by follow-up of 899 Chamorros in the Mariana Islands who participated in a baseline medical examination and interview in 1968. During a 15-year follow-up period, 28 new neurologically confirmed cases occurred, including 23 with parkinsonism-dementia and five with amyotrophic lateral sclerosis. The low incidence of amyotrophic lateral sclerosis was consistent with the reported disappearance of this disease from the Mariana Islands. However, the continuing high incidence of parkinsonism-dementia was not in agreement with a similarly reported disappearance nor with the hypothesis of a common cause of both diseases. Of 23 selected baseline examination variables, only the preference for traditional Chamorro food was significantly associated with an increased risk of parkinsonism-dementia. A review of the accumulated epidemiologic data on these neurologic diseases in the Mariana Islands did not support the current hypothesis that a chronic nutritional deficiency of calcium is a cause of both amyotrophic lateral sclerosis and parkinsonism-dementia.

Analysis, occurrence, and toxicity of ß-methylaminoalanine (BMAA)

“…Both these theories could agree with the epidemiological finding reported above that the only risk factor for ALS-PDC on Guam and Rota identified among 23 investigated factors was the preference for traditional Chamorro food (Reed et al, 1987).…”

“…Reed et al (1987) observed a higher than expected occurrence of both ALS and PD in Filipino migrants to Guam, as long as 29 years after their arrival. noted that of six Filipino and three US white men who arrived to the island and subsequently developed motor neuron disease, seven arrived in the late 1940s, one in 1956 and one in 1963.…”

“…Furthermore, a role for mineral deficiency in the development of ALS-PDC on Guam is negated by a neuropathologic study of neurofibrillary degeneration of selected neurons in brains of 69 deceased Chamorro natives of Guam without known clinical evidence of ALS, PD or dementia (Reed et al, 1987). This study revealed a high prevalence of neurofibrillary degeneration, 29% in persons aged 30-39 and 100% in persons aged 80-89.…”

“…In the investigated population, five prevalent cases of ALS-PDC were diagnosed in 1969. In a follow-up 15 years later, in 1983, four new confirmed cases of ALS, one with ALS-PDC and 23 with PD were identified among those persons that could be traced (Reed et al, 1987).…”

The neurotoxin BMAA in aquatic systems : analysis, occurrence and effects

“…ALS-PDC incidence among the Chamorro people was about 100 times higher than in the continental United States [40], and was related to the Chamorro traditional diet, of which cycad seeds were a main constituent [41]. BMAA was found in dietary items such as cycad flour that was prepared from washed seeds, and flying foxes, a bat species that foraged on cycad seeds and that was regarded as a delicacy by the Chamorro people [42,43].…”