Air Pollution Linked to Higher Risk of Neurodegenerative Diseases in Scandinavia

Two recent studies from Sweden and Denmark show that long‑term exposure to air pollution increases both the risk of developing neurodegenerative disorders and the speed of their progression.

A Karolinska Institute analysis of 1,463 Swedish ALS patients (2015‑2023) compared with healthy controls and siblings found a 20‑30 % higher likelihood of ALS when exposed to higher levels of nitrogen dioxide and fine particulate matter, especially from traffic. The same pollutants were associated with faster loss of motor and respiratory function, leading to earlier need for ventilatory support.

A separate investigation using Danish national registers of more than 2.1 million people aged 65‑95 linked incremental rises in fine particles (PM₂.₅) and nitrogen dioxide to a markedly greater risk of Lewy Body disease and Parkinson‑related dementia. A 5 µg/m³ increase in PM₂.₅ nearly quadrupled Lewy Body disease risk and doubled dementia risk, while a 10 µg/m³ rise in NO₂ roughly doubled Lewy Body disease risk. Researchers note that inhaled particles can enter the bloodstream, cross the blood‑brain barrier, trigger inflammation, and accelerate neurodegeneration.