People who live on busy roads are more likely to develop dementia, large-scale study finds
People who live on or near busy roads are much more likely to develop dementia, according to new research.
The study, published in The British Medical Journal (BMJ), is one of the largest of its kind after scientists analysed data from more than 16 million adults.
It found that even exposure to small amounts of air pollution below current UK, US and European safety limits can be a causal factor in developing dementia.
“Given the massive numbers of dementia cases, identifying actionable, modifiable risk factors to reduce the burden of disease would have tremendous personal and societal impact,” said lead author, Harvard professor Marc Weisskopf.
“Exposure to PM2.5 and other air pollutants is modifiable to some extent by personal behaviours – but more importantly through regulation.”
Toxic particles from diesel fumes, wood smoke, brake pads, tyres and road dust are the leading environmental risk factor for the disease.
The particles get into the blood through the lungs, making it more sticky and can trigger inflammation.
Results from the study suggest those with more exposure to these particles have a 42% greater risk of dementia than those who don’t live near busy roads.
The study is the first to screen entire populations followed by personal evaluation for dementia among individuals who were healthy at the outset.
“This is a big step in providing actionable data for regulatory agencies and clinicians in terms of making sense of the state of the literature on this hugely important health topic,” explained Prof. Weisskopf.
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“The results can be used by organisations like the Environmental Protection Agency (EPA), which is currently considering strengthening limits on PM2.5 exposure. Our findings support the public health importance of such a measure.”
PM2.5 is the name for particles smaller than approximately 2.5 microns, which is so small that billions can fit inside a red blood cell, according to McGill University. In terms of air pollution, PM2.5 kills the most people worldwide.
According to the NHS, around 850,000 people in the UK have dementia – one in 14 people over the age of 65, and one in six people over the age of 80.
It says that the number of people with dementia is increasing because people are living longer. By 2025, it is estimated there will be one million people living with dementia in the UK.
“Reductions in air pollution are theoretically achievable through global environmental policy programmes that focus on transition to clean and renewable energy sources, reduced energy consumption and changes in agriculture,” says professor Andrew Sommerlad, a psychiatrist at University College London who was not involved in the project.
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“Any positive effect on dementia and general health would be accompanied by an important impact on climate change and biodiversity, therefore, reducing air pollution should be a global health and humanitarian priority.”
Air pollution has been linked to all major life-threatening illnesses including cardiovascular disease, cancer and diabetes.
Additional reporting by SWNS.
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