We brought together neurologists, epidemiologists and experts on the effects of toxins in the brain to help us make sense of the research on air pollution and dementia so far.
Research to date has linked air pollution to a wide range of health conditions, in particular respiratory and cardiovascular disease but also to certain forms of cancer and developmental disorders. Polluted air has also been implicated in impaired brain function and potentially dementia.
While there’s a lot of hot air and foggy reasoning out there, we at Alzheimer’s Society wanted to get a clear view of the facts. We brought together a panel of experts in neurology, epidemiology, environmental risk, and how metals behave in the brain, to advise us within a new report.
What is air pollution?
Air pollution refers to substances that are present in the air, or have entered the air, which have harmful effects. Air pollution can come from many sources and travel across distances, and it can interact with other molecules with various consequences.
Most research into whether air pollution is linked to dementia has been through studies of large populations, and there are limitations to them. Many base their findings on where a person is currently living, without taking into account the level of pollution at any previous addresses or at their workplace.
These studies are often also retrospective – they look back on what has happened in a person’s life, rather than recruiting them and seeing how their health then changes over time. The latter gives researchers a better chance to observe cause and effect and ability to rule out coincidence.
An indirect link?
Though research to date has not shown how air pollution could directly cause dementia, evidence does point towards an indirect cause.
It is likely that the effect of air pollution on our respiratory and cardiac health has a knock-on effect on brain health, increasing our risk of developing dementia.
More research is required
There is some evidence that particles from air pollution might be able to enter a person’s brain. If these triggered a toxic response in the brain, this might cause damage that in turn increases the risk of dementia. However, we need more research to find out if this is really the case.
We do know that air pollution has a negative effect on our health, and it is encouraging to see more political engagement with this topic.
The infographic suggests how we can limit our exposure to air pollution on an individual level.
Read the full report
Our report shows that the experts agreed evidence to date supports several possible ways that pollution could be indirectly associated with dementia.