Study Links Air Pollution to Increased Dementia Risk in Denmark

Results from a new study suggest that long-term exposure to air pollution leads to an increased risk of dementia in Denmark.

"We also find an association with noise, but this seems to be explained by air pollution primarily. Our study is in line with growing international knowledge on this topic," says Professor at the Section of Environmental Health, Zorana Jovanovic Andersen.

This is an important finding which adds that air pollution, beyond well-known effects on the respiratory and cardiovascular systems, also has major impacts on our brain, promoting inflammation in the brain, accelerating cognitive decline, and increasing the risk of dementia.

"This is the first study in Denmark showing a link between air pollution and dementia. Although air pollution levels in Denmark have been declining and are relatively low compared to the rest of Europe and the world, this study shows that there are still significant and concerning health effects that demand more action and policies towards the reduction of air pollution. As we are going to live longer, and more and more people will be diagnosed with dementia, this finding is important as it offers an opportunity to prevent new dementia cases and ensure more healthy aging by cleaning up the air we breathe," says Zorana Jovanovic Andersen.

An Internationally Unique Study

The study followed a cohort of nurses for 27 years, from 1993 until 2020.

"This is internationally unique and necessary in regards to the development of dementia which can take many years. Second, the air pollution was estimated for each participant for a total of 41 years (from 1979 until 2020), which is also incredible. Third, we had extensive details about participants’ lifestyle and socio-economics, and all our results take them into consideration. The novelty of this study is the very detailed and accurate data that we used," says Research Assistant from the Section of Environmental Health, Stéphane Tuffier.

"Nurses with higher physical activity had a lower risk of dementia when exposed to air pollution compared to nurses with less physical activity. This indicates that physical activity might mitigate the adverse effects of air pollution on cognitive decline and risk of dementia," Tuffier says.

Reference

Stéphane Tuffier, Jiawei Zhang, Marie Bergmann, Rina So, George Maria Napolitano, Thomas Cole-Hunter, Matija Maric, Sonja Antic, Jørgen Brandt, Matthias Ketzel, Steffen Loft, Youn-Hee Lim, Zorana Jovanovic Andersen, Long-term exposure to air pollution and road traffic noise and incidence of dementia in the Danish Nurse Cohort, Alzheimer's & Dementia, https://doi.org/10.1002/alz.13814.