One in four dementia deaths in 2023 linked to air pollution

Air pollution accounted for more than one-fourth of dementia deaths globally in 2023, according to a report released by the Neuro Climate Working Group. The study quantifies the economic and cognitive costs of environmental exposure, moving beyond traditional respiratory and cardiovascular metrics to focus on neurological outcomes. For households, these findings translate to a potential burden of reduced executive function, increased mental health risks, and higher long-term care expenses.

The report was developed by fifty global experts over a two-year period. Burcin Ikiz, Ph.D., who leads the working group, stated that brain health has been a blind spot in climate policy. She noted that existing environmental regulations rarely include mechanisms to protect cognitive development or prevent neurodegenerative decline. The group sought to make these invisible impacts visible by compiling data on how environmental factors affect the brain.

Extreme heat, air pollution, and extreme weather events represent the primary environmental exposures affecting brain health. Ikiz explained that particulate matter 2.5 and associated chemicals can impact fetal neurodevelopment and increase the risk of stroke and dementia in adults. The study also links water and soil contamination from floods and wildfires to neurological damage. Vector-borne diseases transmitted by mosquitoes and ticks were identified as additional risks.

The report includes accounts from communities facing these exposures. A psychiatrist in Mauritania described the mental health impacts of extreme heat exceeding 110 degrees Fahrenheit for months at a time. In Türkiye, farming communities reported that long periods of drought altered family values and generational livelihoods. A doctor in Kenya observed a child’s mental health decline following a flood, which required the family to provide extended care.

Policy implications focus on measuring brain health outcomes in environmental regulations. Ikiz cited a study showing that clean air regulations in New York City during the 1990s and 2000s improved children’s cognition scores. Similar results were observed in China after strict air regulations were implemented in 2015, which correlated with lowered dementia and suicide rates. The working group proposes that brain health metrics be integrated into assessments of carbon emissions and clean air standards to define the cost of inaction.

The Neuro Climate Working Group also contributed to the World Health Organization’s dementia prevention guidelines. The second version of those guidelines, released a few months ago, lists air pollution as the first modifiable environmental risk factor. The report aims to provide policymakers with the specific data needed to evaluate the economic burden of climate change on public health and workforce productivity.