Lancet study shows living near busy roads increases risk of dementia

Credit: Autonet

Researchers in Ontario, Canada have discovered that people who live near busy roads have an increased risk of dementia. Among those living within 50 metres of a main road there was a 7% higher risk. Between 50-100 metres the risk fell to 4%, & between 101-200 metres, down to 2%. No increase in risk was detected beyond 200 metres.

This was no small study – over 6 million people were tracked over the 10 years ending in 2012.

Although demonstrating an association between proximity to busy roads & dementia, this study does not suggest a mechanism. One possibility is provided by a small study (37 people), which shows that magnetite nanoparticles (abundant in the airborne pollution found in urban settings, especially next to busy roads) in human brains are also associated with diseases such as dementia.¹

Whatever the cause, electric cars are most likely not implicated – one more reason to hurry their widespread adoption.

Something else not defined in any of the references I have been able to locate is a, “major road”.

There is a positive aspect to this study – the incidence of multiple sclerosis & Parkinson's disease were also monitored, but no association was detected.

The Sydney Morning Herald – “Living near busy roads increases dementia risk: Lancet study”, http://www.smh.com.au/national/health/living-near-busy-roads-increases-dementia-risk-lancet-study-20170105-gtm8r1.html

The Guardian – “Living near heavy traffic increases risk of dementia, say scientists”
https://www.theguardian.com/society/2017/jan/04/living-near-heavy-traffic-increases-dementia-risk-say-scientists

Lancet article – if you don’t already have access, be prepared to pay for anything more than a summary http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)32399-6/fulltext
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¹ CNBC: “Alzheimer's link? Study finds air pollution particles in human brain”, https://www.cnbc.com/2016/09/06/alzheimers-link-study-finds-air-pollution-particles-in-human-brain.html / living near busy roads increases dementia risk Lancet study dementia more common people who live near main roads major study raising more concern impacts impact traffic pollution people's health researchers tracked 6.6 million people Ontario Canada decade 2012 closer people lived busy roads greater their risk dementia 7 per cent higher risk developing dementia living within 50 metres main road 4 per cent higher risk at 50-100 metres 2 per cent higher risk 101-200 metres no increase risk living more than 200 metres away study highlights association air pollution experts crucial global health concern millions of people warranted further investigation preventative measures could be found Dr Hong Chen lead author research published The Lancet busy roads source environmental stressors may give rise to dementia increasing population growth urbanisation placed many people close heavy traffic widespread exposure traffic growing rates dementia modest effect from near road exposure pose large public health burden more research understand link needed effects different aspects traffic air pollutants noise researchers long-term exposure two common pollutants nitrogen dioxide fine particulate matter associated with dementia other scientists linked air pollution traffic noise reduced brain matter lower cognition first study investigate connection between living near heavy traffic onset major neurodegenerative diseases good news researchers found no link living close to major roads Parkinson's disease multiple sclerosis research designed control people's wealth education levels body mass index smoking link explained factors researchers could not eliminate all potential confounding factors Professor Michael Woodward director aged care research Austin Health chief medical advisor Alzheimer's Australia dementia linked lower socio-economic socioeconomic socio economic status chronic stress insomnia factors more common people living near main roads study prove traffic pollution caused dementia knock-on effect respiratory cardiovascular problems linked living built-up environments dementia linked cardiovascular problems Professor Woodward study trigger more research toxin cause dementia new target preventative drug treatment issue public health warnings living near heavy traffic busy road dementia /