In 2021, the World Health Organization (WHO) announced that climate change is the biggest global health threat to humanity¹. The planet has already seen a myriad of unprecedented weather, and experts are aware this is just the tip of the melting iceberg.

Disease Pathology in a Warmer Climate

As biological organisms, we are sensitive to changes in our environment. A 1.5°C ambient temperature increase may not influence what jacket you wear but could induce acclimatization effects on neural pathways and mechanisms that underlie normal brain functioning. These pathways are implicated in neurodegeneration, including oxidative stress, excitotoxicity, and neuroinflammation². A characteristic and biomarker of many neurodegenerative diseases is protein misfolding or aggregation, which may be accelerated by heat stress. Further, heat shock proteins (HSPs) play an important role in mitigating protein misfolding. Constant exposure to heat can induce dysregulation of these proteins and a failure to control destructive protein accumulations².

A review on studies investigating climate change and neurodegeneration found evidence that a 1.5°C increase in mean ambient temperature correlated with more hospital admissions for dementia of Alzheimer’s type (DAT) disease patients³. Higher temperatures may accelerate Tau phosphorylation, a characteristic of Alzheimer’s disease, serving as a potential explanation for increased disease severity⁴.

Similarly, alpha synuclein aggregations are a hallmark of Parkinson’s disease. Their presence correlates with symptom central thermoregulatory alteration⁵. Heat stress may exacerbate this – as well as neuroinflammation, which affects disease progression⁶. A follow up study confirmed that there is a statistically sound link between climate change and the epidemiological data of Parkinson’s disease patients⁷.

Toxicants, Migration, and Local Environments

Temperature is not the only aspect of our environment that is changing. Levels of toxicants such as neurotoxic metals, pesticides and metal-based nanoparticles have increased substantially in recent years. According to a review conducted by researchers at the University of Kashmir in India, exposure to these toxins may heighten the risk of developing neurodegenerative disorders⁸. These compounds can disrupt the blood-brain barrier, affect protein aggregation, and induce oxidative stress – converging to invoke disease characteristics⁸.

As climatic catastrophes occur, parts of the world may become inhabitable. A study conducted by researchers in Copenhagen found that the impact of human migration on the incidences of neurological disorders is “non-uniform but substantial”⁹. They suggest migration could lead to psychological trauma that may adversely impact access to health care, and subsequent neurological health outcomes. Further, climatic refugees may be exposed to novel external agents, posing potential health risks that are not yet understood.

            “The known issue is that global warming is increasing stress and uncertainty, [which] potentiate conditions like Alzheimer’s disease,” said professor Dr. George Perry in an interview with Medical News Today.¹⁰

Degradation of local environments could adversely affect age-related neurodegenerative outcomes. Data from a Belgian census revealed an association between surrounding greenness and premature mortality from all neurodegenerative diseases¹¹. Notably, these associations were strongest for socioeconomically disadvantaged groups¹¹. Thus, an individual’s exposure to green space in their immediate environment may provide some protection against these health threats, conversely a lack thereof, may accelerate them.

The Future

A warming climate will have direct implications on complex neural pathways. Further, the coinciding environmental changes will inevitably induce stress. These events could have a major impact on the most prevalent neurodegenerative diseases, such as Alzheimer’s, Dementia, and Parkinson’s disease, including accelerating disease progression. Yet, lack of data suggests a greater awareness and well-designed research on the issue is necessary¹⁰.

StressMarq manufactures a range of proteins for neurodegenerative disease research related to the alterations that the warming environment may create. These include Alpha Synuclein, Tau and Amyloid Beta monomers, oligomers, and pre-formed fibrils.

References

1. Climate change and Health, 2021.
2. Climate change and neurodegenerative diseases, Bongioanni, P. et al. Environmental Research. 2021; (201)111511.
3. Associations between seasonal temperature and dementia-associated hospitalizations in New England, Wei, Y. et al. Environment International. 2019; (126)228-233.
4. Hypothermia and Alzheimer’s Disease Neuropathogenic Pathways. Whittington R. et al. Current Alzheimer Research. 2010; 7(8).
5. Neuropathy and levodopa in Parkinson’s disease: Evidence from a multicenter study, Ceravolo, R. et al. Movement Disorders. 2013; (28)1391-1397.
6. Alteration of brain temperature and systemic inflammation in Parkinson’s disease, Chen, H.L. et al. Neurological Sciences. 2020; (41)1267–1276.
7. Evidence of Climate Change Impact on Parkinson’s Disease, Buizza, R. et al. The Journal of Climate Change and Health. 2021; (6)100130.
8. Role of Environmental Toxicants on Neurodegenerative Disorders, Nabi, M. & Tabassum, N. Frontiers in Toxicology. 2022; (4)837579.
9. Global warming and neurological practice: systematic review, Amiri, M. et al. 2021; (9)11941.
10. Climate change: Impact of rising temperatures on neurological disorders, Deep Shukla. Medical News Today. 2021.
11. Long-term exposure to residential greenness and neurodegenerative disease mortality among older adults: a 13-year follow-up cohort study, Rodriguez-Loureiro, L., et al.Environment Health. 2022; 21:49.