Heavy Traffic And A Possible Link With Dementia

The Guardian has an article here about a possible link between heavy traffic and dementia:

People living near a busy road have an increased risk of dementia, according to research that adds to concerns about the impact of air pollution on human health.

Roughly one in 10 cases of Alzheimer’s in urban areas could be associated with living amid heavy traffic, the study estimated – although the research stopped short of showing that exposure to exhaust fumes causes neurodegeneration.

Hong Chen, the scientist who led the work at Public Health Ontario, said: “Increasing population growth and urbanisation has placed many people close to heavy traffic, and with widespread exposure to traffic and growing rates of dementia, even a modest effect from near-road exposure could pose a large public health burden.”

Previously, scientists have linked air pollution and traffic noise to reduced density of white matter (the brain’s connective tissue) and lower cognition. A recent study suggested that magnetic nano-particles from air pollution can make their way into brain tissue.

The latest study, published in The Lancet, found that those who live closest to major traffic arteries were up to 12% more likely to be diagnosed with dementia – a small but significant increase in risk.

The study, which tracked roughly 6.6 million people for more than a decade, could not determine whether pollution is directly harmful to the brain. The increased dementia risk could also be a knock-on effect of respiratory and cardiac problems caused by traffic fumes or due to other unhealthy life-style factors associated with living in built-up urban environments…..

All this research shows is that, after allowing other factors such as wealth and other health issues, there seems to be a small increased risk of dementia. However it’s not clear whether it’s caused by air pollution, or by noise that disturbs people’s sleep patterns. Or it could even be that people who are more susceptible to dementia simply have a preference for living in busier, more bustling environments , or that people at less risk of dementia have an underlying wish to live in quieter places….