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An increased risk of Parkinsonism among firefighters has been reported by researchers from Tufts University (see Kotwani et al., 2022). The study which used an anonymous survey to collect self reported data found that metrics reflecting cumulative/duration of exposure including the number of years working as a firefighter, the number of days per week working, and the number of fires worked correlated with higher reports of Parkinsonian symptoms such as hyposmia, micrographia, and decreased walking pace. Reports of pesticide exposure were also significantly correlated with decreased walking pace, micrographia, and hyposmia among these firefighters. This observation is consistent with findings other studies linking exposures to pesticides and herbicides to Parkinson’s disease. Participation in the Vietnam War which involved risk for exposure to Agent Orange, was also significantly correlated with decreased walking pace and micrographia in this study. These findings add to the growing body of literature implicating occupational exposures to neurotoxicants in the risk for Parkinsonism and Parkinson's disease.
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British farmers call for a ban on production of Paraquat citing link to onset of Parkinson's Disease.
The BBC is reporting on British farmers calling for a ban on the production of Paraquat in the UK saying studies suggest it could be a factor in the onset of Parkinson's Disease. Paraquat was first manufactured in the UK in the early 1960s.
Hundreds of US farm workers are currently pursuing a legal case against the manufacturer of paraquat alleging the manufacture knew the risks and failed to warn consumers. The manufacture says claims of a link between Paraquat and Parkinson's are not supported by scientific evidence. Although many epidemiological studies have looked for a link between the risk for developing Parkinson's disease among workers exposed to paraquat, few have looked at the age at onset.
Julie Plumley's father John was diagnosed with Parkinson's in his 40s. His neighbour Ken Barnes was diagnosed around the same time - he was also in his 40s and had also been using Paraquat for years. Ratner et al., 2014 and Gamache et al., 2019 also observed that exposure to pesticides including paraquat is associated with a younger age at onset of Parkinson's disease.
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Coffee, smoking and aspirin are associated with older age at onset of idiopathic Parkinson’s disease
New research from Carolin Gabbert, and colleagues published in the Journal of Neurology indicates that drinking coffee, smoking and aspirin usage are associated with age at onset in idiopathic Parkinson’s disease. In contrast to the findings for coffee, black tea drinking was not associated with age at onset. The association of ibuprofen was not as strong as the association with aspirin while other anti-inflammatory medications showed no association at all with AAO. These findings are consistent with previous research by Ratner et al., 2014 who also found smoking to be associated with a later onset of sporadic Parkinson’s disease. These findings add to the growing body of evidence implicating environmental factors in the age at onset of Parkinson’s disease.
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Link to Ratner et al. 2014
Dr. Marcia Ratner of Neurotoxiants.com and Dr. James Hendrix of LuMind IDSC were recently interviewed by Dr. Hackie Reitman of DifferentBrains about their thoughts on the state of the art in Alzheimer's research.
Geospatially Estimating of Exposure to Crop-Applied Pesticides finds Increased Risk for Amyotrophic Lateral Sclerosis
A large study by Andrew and colleagues looking at the risk for Amyotrophic Lateral Sclerosis (ALS) based on geospatially estimating exposure to crop-applied pesticides has found an association with several neurotoxic herbicides, insecticides, and fungicides. The study looked at residence at diagnosis of approximately 26,000 nationally distributed ALS patients, and matched non-ALS controls. The he residency data was then related to pesticide exposure risk based on county-level U.S. Geological Survey data on applications of 423 pesticides. The authors concluded that's their findings are consistent with the hypothesis that certain pesticides have neurotoxic effects that increase risk of neurodegenerative disease. Although this study did not look at duration or magnitude of pesticide exposure as this relates to age at onset of ALS, it nevertheless provides additional support for neurotoxic chemical exposures as risk factors for this neurodegenerative disease.
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Altered Hippocampal Response to Systemic Administration of an α5 type GABA-A Receptor Modulator in a Rat Model of Alzheimer’s disease
α5 subunit containing GABA type A receptors (a5GABAARs) are highly expressed in the hippocampus of humans and animals. The functioning of these receptors is altered in neurodevelopmental disorders including autism and by neuroinflammation and injuries to the brain (reviewed by Jacobs 2019). Ratner and colleagues (Heliyon, 2021) show for the first time that systemic administration of a5IA, a selective negative modulator of a5GABAARs, increases peak ripple amplitudes in wild type adult rats but has no effect on peak ripple amplitudes in the TgF344-AD rat model of Alzheimer's disease which also shows elevated plasma concentrations of AB42 and AB40 during the prodromal state of the disease when memory function is still intact. These findings demonstrate the selective sensitivity of the healthy versus diseased hippocampus to chemicals that modulate inhibitory neurotransmission. These findings also indicate that tonic inhibitory neurotransmission is altered in this highly translational rat model of Alzheimer's disease.
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Alzheimer's patients treated with ANVS401 showed significant improvement in cognition as measured by the Alzheimer's Disease Assessment Scale-Cognitive Subscale 11 (ADAS-Cog11). ANVS401 also significantly increased speed, coordination and motor function in Parkinson's patients enrolled in in this trial. ANVS401acts by improving axonal transport. Neurotoxic chemicals that disrupt axonal transport such as n-hexane are implicated in Parkinson's (see Pezzoli et al., 1995). Reducing exposure to these chemicals is associated with an increase in the age at onset of PD (see Pezzoli et al., 2014). These findings add additional support to the role of chemical exposures as disease modifiers in neurogenerative disease.
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I am pleased to share our most recent publication which appears in the America Journal of Industrial Medicine titled "A rare case of Holmes tremor in a worker with occupational carbon monoxide poisoning". In this report we present a rare case of toxic encephalopathy and Holmes-type tremor, in a previously healthy 53-year-old man who was exposed to carbon monoxide while using a concrete saw in a small unventilated space. Holmes tremor is characterized by resting, as well as postural and kinetic/intentional components. Specific lesions sites associated with Holmes tremor include the cerebellum, red nucleus, thalamus, and globus pallidus. The globus pallidus is also vulnerable to carbon monoxide poisoning. This patient's symptoms were ameliorated with the D2 preferring dopamine receptor agonist ropinirole. This case report serves as reminder of the dangers associated with exposure to carbon monoxide in occupational settings.
Link to citation in PubMed
Working as a mechanic, painter and construction worker associated with 2-fold increased risk of Amyotrphic Lateral Sclerosis.
A new report appearing in Muscle and Nerve by Angeline Andrew and other members of Elijah Stommel's team at Dartmouth indicates that exposure to the heavy metal neurotoxicant lead and working as a mechanic, painter or construction worker (jobs with increased risk for exposure to industrial chemicals) are associated with greater risk for ALS. Head injury and electrical burns were also associated with an increased risk for ALS.
Although this study, which was funded by the Centers for Disease control (CDC) and the Agency for Toxic Substances and Disease Registry (ATSDR) did not look at duration or intensity of exposure in relationship to age at onset of symptoms, it nevertheless adds to the growing body of literature implicating prior exposure to neurotoxic chemicals such a lead and industrial solvents found in paints in the risk for developing ALS.
Link to original article in Muscle and Nerve
A new prospective cohort study by Diana Younan and colleagues published in the journal Neurology has found that older women without dementia who are exposed later in life to air pollution consisting of microscopic particles of chemicals, smoke, dust and other pollutants < 2.5 μm in diameter have an increased risk for neuroanatomical changes associated with Alzheimer's disease (AD). The study used MRI data combined with supervised machine learning to measure brain atrophy in areas vulnerable to AD. The observed increased risk could not be explained by geographic region; race; ethnicity; highest education level obtained; smoking or alcohol use; physical activity; BMI scores; diabetes; use of hormone replacement therapy nor by an MRI-measure of cerebrovascular damage.
These data add to the growing body of literature implicating exposure to neurotoxicants in the neuropathogenesis of neurodegenerative diseases such as AD.
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Dr. Marcia Ratner shares and reviews the news.