Study: Air pollution exposure harms brain health in older adults

Long-term exposure to air pollution may damage the brain health of seniors, according to new research from University College London. The study, published in The Journals of Gerontology: Series A, found that older adults exposed to high levels of nitrogen dioxide and fine particulate matter experienced notable declines in cognitive performance, particularly in language abilities.

Researchers analyzed data from 1,127 adults aged 65 and over who participated in the English Longitudinal Study of Ageing (ELSA) Harmonised Cognitive Assessment Protocol in 2018. The team examined participants’ exposure to air pollution over eight to 10 years and assessed their memory, executive function, language skills and overall cognitive function through various neurocognitive tests.

The findings revealed that seniors living in areas with the highest pollution levels scored significantly lower on cognitive tests compared to those in areas with average pollution. According to study authors, these cognitive effects are significant because aging-related decline in cognitive function contributes to reductions in life expectancy, quality of life and social participation. The study also cited previously reported statistics showing that the population-attributed fraction for air pollution in dementia is estimated at 2.6% — a higher figure than that calculated for hypertension and physical inactivity. The strongest evidence of harm was seen in language abilities, with individuals in highly polluted areas performing in the lower third of the range on language-related cognitive tests.

The study also uncovered that different pollution sources affect cognitive health in various ways. Pollution from industries, home heating, and combustion of fuels such as coal and oil were strongly linked to poorer language performance.

“Our study shows that air pollution is not just harmful to the lungs and heart but also to brain health, especially when people are exposed to high levels for long periods,” said lead author Giorgio Di Gessa, PhD, UCL Epidemiology & Health.

Professor Paola Zaninotto, PhD, deputy director of the ELSA study, added: “By tracking pollution levels over a decade using high-quality data, our research provides robust evidence that sustained exposure to pollutants is damaging people’s brains.”