Geographic patterns of parkinsonism-dementia complex on Guam. 1956 through 1985

The role of geographic information system and global positioning system in dementia care and research: a scoping review

Background

Geographic Information System (GIS) and Global Positioning System (GPS), vital tools for supporting public health research, provide a framework to collect, analyze and visualize the interaction between different levels of the health care system. The extent to which GIS and GPS applications have been used in dementia care and research is not yet investigated. This scoping review aims to elaborate on the role and types of GIS and GPS applications in dementia care and research.

Methods

A scoping review was conducted based on Arksey and O’Malley’s framework. All published articles in peer-reviewed journals were searched in PubMed, Scopus, and Web of Science, subject to involving at least one GIS/GPS approach focused on dementia. Eligible studies were reviewed, grouped, and synthesized to identify GIS and GPS applications. The PRISMA standard was used to report the study.

Results

Ninety-two studies met our inclusion criteria, and their data were extracted. Six types of GIS/GPS applications had been reported in dementia literature including mapping and surveillance (n = 59), data preparation (n = 26), dementia care provision (n = 18), basic research (n = 18), contextual and risk factor analysis (n = 4), and planning (n = 1). Thematic mapping and GPS were most frequently used techniques in the dementia field.

Conclusions

Even though the applications of GIS/GPS methodologies in dementia care and research are growing, there is limited research on GIS/GPS utilization in dementia care, risk factor analysis, and dementia policy planning. GIS and GPS are space-based systems, so they have a strong capacity for developing innovative research based on spatial analysis in the area of dementia. The existing research has been summarized in this review which could help researchers to know the GIS/GPS capabilities in dementia research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12942-022-00308-1.

Toxic Damage to Motor Neurons

Abstract—Amyotrophic lateral sclerosis (ALS) is a multifactor disease in the development of which both genetic and environmental factors play a role. Specifically, the effects of organic and inorganic toxic substances can result in an increased risk of ALS development and the acceleration of disease progression. It was described that some toxins can induce potentially curable ALS-like syndromes. In this case, the specific treatment for the prevention of the effects of the toxic factor may result in positive clinical dynamics. In this article, we review the main types of toxins that can damage motor neurons in the brain and spinal cord leading to the development of the clinical manifestation of ALS, briefly present historical data on studies on the role of toxic substances, and describe the main mechanisms of the pathogenesis of motor neuron disease associated with their action.

A critical review of the postulated role of the non-essential amino acid, β-N-methylamino-L-alanine, in neurodegenerative disease in humans

The compound BMAA (β-N-methylamino-L-alanine) has been postulated to play a significant role in four serious neurological human diseases: Amyotrophic Lateral Sclerosis/Parkinsonism Dementia Complex (ALS/PDC) found on Guam, and ALS, Parkinsonism, and dementia that occur globally. ALS/PDC with symptoms of all three diseases first came to the attention of the scientific community during and after World War II. It was initially associated with cycad flour used for food because BMAA is a product of symbiotic cycad root-dwelling cyanobacteria. Human consumption of flying foxes that fed on cycad seeds was later suggested as a source of BMAA on Guam and a cause of ALS/PDC. Subsequently, the hypothesis was expanded to include a causative role for BMAA in other neurodegenerative diseases including Alzheimer's disease (AD) through exposures attributed to proximity to freshwaters and/or consumption of seafood due to its purported production by most species of cyanobacteria. The hypothesis that BMAA is the critical factor in the genesis of these neurodegenerative diseases received considerable attention in the medical, scientific, and public arenas. This review examines the history of ALS/PDC and the BMAA-human disease hypotheses; similarities and differences between ALS/PDC and the other diseases with similar symptomologies; the relationship of ALS/PDC to other similar diseases, studies of BMAA-mediated effects in lab animals, inconsistencies and data gaps in the hypothesis; and other compounds and agents that were suggested as the cause of ALS/PDC on Guam. The review concludes that the hypothesis of a causal BMAA neurodegenerative disease relationship is not supported by existing data.

Geographical variation in dementia: systematic review with meta-analysis

BACKGROUND

Geographical variation in dementia prevalence and incidence may indicate important socio-environmental contributions to dementia aetiology. However, previous comparisons have been hampered by combining studies with different methodologies. This review systematically collates and synthesizes studies examining geographical variation in the prevalence and incidence of dementia based on comparisons of studies using identical methodologies.

METHODS

Papers were identified by a comprehensive electronic search of relevant databases, scrutinising the reference sections of identified publications, contacting experts in the field and re-examining papers already known to us. Identified articles were independently reviewed against inclusion/exclusion criteria and considered according to geographical scale. Rural/urban comparisons were meta-analysed.

RESULTS

Twelve thousand five hundred and eighty records were reviewed and 51 articles were included. Dementia prevalence and incidence varies at a number of scales from the national down to small areas, including some evidence of an effect of rural living [prevalence odds ratio (OR) = 1.11, 90% confidence interval (CI) 0.79-1.57; incidence OR = 1.20, 90% CI 0.84-1.71]. However, this association of rurality was stronger for Alzheimer disease, particularly when early life rural living was captured (prevalence OR = 2.22, 90% CI 1.19-4.16; incidence OR = 1.64, 90% CI 1.08-2.50).

CONCLUSIONS

There is evidence of geographical variation in rates of dementia in affluent countries at a variety of geographical scales. Rural living is associated with an increased risk of Alzheimer disease, and there is a suggestion that early life rural living further increases this risk. However, the fact that few studies have been conducted in resource-poor countries limits conclusions.

Guam dementia syndrome revisited in 2011

PURPOSE OF REVIEW

This review covers the amyotrophic lateral sclerosis (ALS)/parkinsonism dementia complex (PDC) of Guam. Clinical and epidemiological characteristics, genetic possible and environmental causes, and neuropathological features of the disease are discussed.

RECENT FINDINGS

Recent studies of clinical syndromes and neuropathological studies are compared with previous descriptions of the disease. The latest genetic and environmental studies are also reviewed.

SUMMARY

In recent years, understanding of the molecular pathogenesis of neurodegenerative diseases has evolved. ALS/PDC shares neuropathological features found in many neurodegenerative diseases such as Alzheimer's disease, Lewy body disease, and frontotemporal lobar degeneration. Thus, examining ALS/PDC may provide further explanations on how various proteins seen in neurodegenerative disorders may be interrelated.

The ALS/PDC syndrome of Guam: potential biomarkers for an enigmatic disorder

The ALS/parkinsonism-dementia complex of Guam is a long latency disease with a diverse phenotypic expression characteristic of classical ALS, parkinsonism and dementia. It is remarkably similar to a syndrome localized to the Kii Peninsula of Japan. There are as yet no identified pathological features that will clearly distinguish the Guam or Kii ALS/PDC syndrome from other degenerative neurological disorders. At present, ALS/PDC of Guam and the Kii Peninsula can be confirmed only by postmortem examination. The most prominent pathological hallmark is the widespread occurrence of neurofibrillary tangles which express the same balance of 3R and 4R tau that is found in Alzheimer disease. They both show an increased prevalence of a peculiar retinal disorder termed linear retinal pigmentary epitheliopathy. The disorders are both highly familial. Several environmental factors have been proposed but no supportive evidence for an environmental or dietary factor has been found. Genome searches have so far failed to identify causative genes although two single nuclear polymorphisms related to MAPT that increase the risk of the Guam syndrome have been located. The two syndromes are clearly unique, and clues as to their causation could be beneficial in understanding the etiology of similar, but much more prevalent disorders in North America, Europe and Asia. Identification of biomarkers for premortem diagnosis would be helpful in management as well as in revealing the true etiology.

On the decline and etiology of high-incidence motor system disease in West Papua (southwest New Guinea)

The etiology of a high-incidence focus of amyotrophic lateral sclerosis and parkinsonism-dementia (ALS/P-D) in south West Papua (Irian Jaya, Indonesia), first described in the 1960s and 1970s, has been attributed to mineral deficiencies, hyperparathyroidism, and metal neurotoxicity arising from reliance on drinking water obtained from springs and shallow wells. More recent visits (1987 and 1990) to the south West Papua focus of neurodegenerative disease cast doubt on this explanation by revealing changes in disease prevalence in communities with an unchanged water supply. These communities have experienced a dramatic decline in ALS and a reversal in the relative prevalence of ALS and parkinsonism. The extrapyramidal disorder can be distinguished from Parkinson disease by pyramidal features (and dementia) reminiscent of Guam P-D. Topical use of cycad seed (termed kurru) gametophyte to treat large skin lesions is advanced as a plausible but unproven etiologic factor. Medicinal use of untreated cycad seed (Cycas sp.) has also been linked with ALS foci in Japan (oral use) and Guam (topical use), with the additional consumption on Guam of food items prepared from Cycas sp. seed or animals that consume cycad seed components.

Elevated levels of ferrimagnetic metals in foodchains supporting the Guam cluster of neurodegeneration: Do metal nucleated crystal contaminents evoke magnetic fields that initiate the progressive pathogenesis of neurodegeneration?

Elevated levels of aluminium (Al), strontium (Sr), barium (Ba), iron (Fe), manganese (Mn) cations - combined with deficiencies of magnesium (Mg)/calcium (Ca) - have been observed in the foodchains that traditionally support the Chamorro populations affected by high incidence clusters of Alzheimer (AD), Parkinson-like (PD), motor neurone diseases and multiple sclerosis on the island of Guam. Soils drawn from the cluster region demonstrated an excessive fivefold increase in 'magnetic susceptibility' readings in relation to soils from disease free adjoining regions. A multifactorial aetiological hypothesis is proposed that pivots upon the combined exposure to high levels of natural/industrial sources of ferrimagnetic/ferroelectric compounds incorporating Al, Fe, Mn, Sr, Ba (e.g., via yam/seafood consumption or exposure to world war 2 (WW2) munitions) and to low levels of Mg/Ca in all S. Pacific locations where these clusters of neurodegenerative disease have simultaneously erupted. Once gut/blood brain barrier permeability is impaired, the increased uptake of Al, Fe, Sr, Ba, or Mn into the Mg/Ca depleted brain leads to rogue metal substitutions at the Mg/Ca vacated binding domains on various enzyme/proteoglycan groups, causing a broad ranging disruption in Mg/Ca dependent systems - such as the glutamine synthetase which prevents the accumulation of neurotoxic glutamate. The rogue metals chelate sulphate, disrupting sulphated-proteoglycan mediated inhibition of crystal proliferation, as well as its regulation of the Fibroblast growth factor receptor complex which disturbs the molecular conformation of those receptors and their regulation of transphosphorylation between intracellular kinase domains; ultimately collapsing proteoglycan mediated cell-cell signalling pathways which maintain the growth and structural integrity of the neuronal networks. The depression of Mg/Ca dependent systems in conjunction with the progressive ferrimagnetisation of the CNS due to an overload of rogue ferroelectric/ferrimagnetic metal contaminants, enables 'seeding' of metal-protein crystalline arrays that can proliferate in the proteoglycan depleted brain. The resulting magnetic field emissions initiate a free radical mediated progressive pathogenesis of neurodegeneration. The co-clustering of these various types of disease in select geographical pockets around the world suggests that all of these conditions share a common early life exposure to ferromagnetic metal nucleating agents in their multifactorial aetiology. Factors such as individual genetics, the species of metal involved, etc., dictate which specific class of disease will emerge as a delayed neurotoxic response to these environmental insults.

Update on epidemiological aspects of progressive supranuclear palsy

The cause of progressive supranuclear palsy (PSP), the most common form of the atypical parkinsonian disorders, is unknown. PSP is characterized by four-repeat tau aggregates in neurons (neurofibrillary tangles) and glia in specific basal ganglia and brainstem areas. A thorough literature review led us to hypothesize that genetic and/or environmental factors contribute to its development. It is likely that inheritance of the H1/H1 tau genotype represents a predisposition to develop PSP requiring other environmental or genetic factors. Less likely, a relatively rare mutation with low penetrance could contribute to the abnormal tau aggregation present in this disorder. The possible role of chemicals in the diet or occupation, hypertension, traumatic brain injury, coffee, and inflammation or oxidative injury are reviewed.

The Guam cycad toxin methylazoxymethanol damages neuronal DNA and modulates tau mRNA expression and excitotoxicity

As in Alzheimer's disease, brains of Guam Chamorros with amyotrophic lateral sclerosis (ALS) and Parkinsonism-dementia complex (PDC) contain intraneuronal-paired helical filaments composed of accumulated phosphorylated tau protein. Tau mRNA expression in rat neuronal cultures-normally modulated by glutamate-increases after treatment with the aglycone of cycasin, a cycad-derived toxin whose concentration in Chamorro food varies with disease incidence. Elevated Tau gene expression in vitro is coincident with increased cycasin-related DNA adducts and reduced DNA repair. Cycasin and endogenous glutamate may together promote the accumulation of tau protein and neuronal degeneration in Western Pacific ALS/PDC.

Motor neuron disease on Guam: geographic and familial occurrence, 1956-85

We investigated the geographic and familial occurrence of motor neuron disease (MND) on Guam, and then considered etiologic hypotheses related to cycad use and metal intoxication. The research was based on 303 Chamorros from Guam and 3 Chamorros from other Mariana Islands, all with MND onset on Guam during 1956-85. Inarajan and Umatac, two southern districts, each had, for both sexes combined, an average incidence rate significantly higher than the corresponding overall rate for Guam. Also, for each sex, geographic patterns of incidence were significantly related to 1) socioeconomic level (men only), 2) cycasin concentrations in cycad flour samples (men and women), 3) iron concentrations in water samples (men and women), 4) silicon concentrations in water samples (men only), and 5) cobalt and nickel concentrations in soil samples (men and women). The MND risk in susceptible sibships was about 7-28 times greater than that in the general population. The cycad hypothesis conforms somewhat better than the metal intoxication hypothesis with the data presented.

Oxidative stress: free radical production in neural degeneration

It is not yet established whether oxidative stress is a major cause of cell death or simply a consequence of an unknown pathogenetic factor. Concerning chronic diseases, as Parkinson's and Alzheimer's disease are assumed to be, it is possible that a gradual impairment of cellular defense mechanisms leads to cell damage because of toxic substances being increasingly formed during normal cellular metabolism. This point of view brings into consideration the possibility that, besides exogenous factors, the pathogenetic process of neurodegeration is triggered by endogenous mechanisms, either by an endogenous toxin or by inherited metabolic disorders, which become progressively more evident with aging. In the following review, we focus on the oxidative stress theory of neurodegeneration, on excitotoxin-induced cell damage and on impairment of mitochondrial function as three major noxae being the most likely causes of cell death either independently or in connection with each other. First, having discussed clinical, pathophysiological, pathological and biochemical features of movement and cognitive disorders, we discuss the common features of these biochemical theories of neurodegeneration separately. Second, we attempt to evaluate possible biochemical links between them and third, we discuss experimental findings that confirm or rule out the involvement of any of these theories in neurodegeneration. Finally, we report some therapeutic strategies evolved from each of these theories.