Air pollution linked with increased dementia risk in Seattle study

Today (Wednesday 4 August) researchers in the US have published findings suggesting that higher levels of air pollution are linked with increased dementia risk.

Air pollutants are extremely small particles and gases in the air that can cause harm to people.

Particulate matter is a type of air pollution made up of solid particles and liquid droplets that are suspended in the air.

Looking at 4,166 volunteers in Seattle, the team linked exposure to particulate matter based on location within the city to dementia risk.

Over the course of the study, 1,136 volunteers developed dementia.

They found that greater exposure to particulate matter was associated with an increased risk of dementia.

Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:

“This study adds to growing evidence of a relationship between air pollution and dementia risk. We know that the diseases that cause dementia can begin up to two decades before symptoms appear. While this research looked at exposure to air pollution over 10 years, the volunteers had an average age of 75 at the start of the study, and future research should explore how air pollution throughout our lives may affect the risk of dementia. “Unpicking the complex lifestyle factors throughout life that contribute to dementia risk will always be tricky. In this long-term study, the team scientists possessed high-quality information on pollution levels where the participants lived. While they worked to account for factors other than air pollution that may underly an association between where people live and their dementia risk, it is difficult to rule these out entirely. “There are a number of biological explanations for why air pollution could be linked to an increased risk in dementia, but researchers didn’t specifically look at these in this study. While this research is based on US data, air pollution is an issue that effects many across the industrialized world and the findings are still relevant to us here in the UK. “As individuals, air pollution is a dementia risk factor that is hard to avoid but can be addressed by wider societal action and legislative change. The findings underlie the importance that reducing air pollution should be a priority for public health authorities.”

Fine Particulate Matter and Dementia Incidence in the Adult Changes in Thought Study by Shaffer et al., in Environmental Health Perspectives