Living Near Heavy Traffic Increases Risk of Dementia, Study Finds (theguardian.com)

An anonymous reader quotes a report from The Guardian: 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. 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. The study tracked all adults aged between 20 and 85 living in Ontario, Canada from 2001 to 2012, using postcodes to determine a person's proximity to major roads. The cohort's medical records were examined to see who went on to develop dementia, Parkinson's disease or multiple sclerosis. Over the study period, more than 243,000 people developed dementia, 31,500 people developed Parkinson's disease and 9,250 people developed multiple sclerosis. The scientists found no link between living near a road and Parkinson's disease or multiple sclerosis, but dementia was slightly more common in people living close to busy roads and the risk dropped off gradually in less built-up areas. Those living within 50 meters of a busy road had a 7% higher risk in developing dementia, the risk was 4% higher risk at 50-100 meters, 2% higher risk at 101-200 meters and there was no increase in risk in those living more than 200 meters away. Those who lived in a major city, within 50 meters of a major road and who did not move house for the duration of the study had the highest risk at 12%.

Comments

I wouldn't live near heavy traffic

[Mr D from 63]

You'd have to be crazy to live there.

Re:I wouldn't live near heavy traffic

[Anonymous Coward]

Heavy traffic in cities. This explains why crowded cities are liberal.

Re:I wouldn't live near heavy traffic

[arglebargle_xiv]

As with almost all mainstream reporting of a medical result, they've mischaracterised the findings. What the study says is that breathing polluted air is a bad thing. One source of pollution is heavy traffic. Other sources of pollution are... well, just about anything related to commerce and industry, Also, pollution causes a lot more than dementia, Parkinson's and MS. However, if it were to be reported as "pollution is bad for you", it wouldn't make the mainstream media.

As an aside, the study is pretty well done, a cohort study of several million people over a ten-year period, nothing to fault there. It's the way it's being reported in the media that's the problem.

Re:I wouldn't live near heavy traffic

[ShanghaiBill]

Or maybe the causation is reversed. Dealing with dementia puts enormous financial strain on families. So they don't have much money for rent, and have to live next to the freeway.

Re: I wouldn't live near heavy traffic

[WarJolt]

You can't prove that. All we know for sure is that demented people live close to highways.

Re:I wouldn't live near heavy traffic

[ShanghaiBill]

It is a tracking study that starts with their location, then sees who later gets diagnosed with diseases

Getting dementia isn't like catching a cold, where one day you are fine, and the next day you got it. Retrospective research has found differences even 30 or 40 years earlier, between people that would later get full Alzheimers and those who never did. It is possible that people who would later be diagnosed with dementia had lower household incomes decades earlier.

Re:I wouldn't live near heavy traffic

[mysticgoat]

If you do a longitudinal study on a thousand people living in an adverse environment, you need to account for the high likelihood that fewer of those with pre-dementia conditions will relocate to better neighborhoods during the study than those with normal mentation. It would be exceedingly hard to adjust a study of this kind to account for this differential out-migration.

In other words, those who have pre-dementia conditions are more likely to remain in an unhealthy environment than the average person. Persons with below average coping skills face higher barriers to relocating. Also, dementia, with its decreased ability to assess one's environment, increases a person's tolerance of negative environmental conditions. So it is also not only more difficult to move away, there is less of a perceived need to do so.

There is a strong "correlation does not imply causation" factor with regard to this study. It has value in strongly suggesting that if you want to find a neighborhood with a higher than average population of demented residents, you should look for places with lots of noise pollution, bad odors, relatively low tax bases, and similar markers of marginal living conditions. But I think we pretty much knew that already.

obvious pun

[shentino]

Well I've heard of driving people crazy but this is ridiculous.

I used to live by one

[Snotnose]

25 years ago, looking for a house for the fiance and I. Ended up buying a house by I-5 on the knowledge Caltrans was going to build a wall between my backyard and the freeway. They did. They took months to do it. Not kidding. Survey team came in, did their thing, then 2-3 months of nothing. Demo team came in to get rid of the existing brick wall, 3 days work, 3 months nothing. Peeps came in to dig holes, suckers were about 8 feet deep. I was worried my cat would fall in one so I had to buy 4-5 plywood sheets to put over the holes. Few months later people actually came in to build the wall. They dumped some iron things into the pool and didn't fish them out, left stains on my pool bottom. Within a year the paint covering started to blister. And the noise. Jeez, the noise.

Got divorced, moved to a quieter neighborhood. Whenever I visited the ex (yeah, she got the house) I couldn't believe the noise in the back yard. You couldn't carry a conversation at normal volume levels.

So, when the real estate dude and anyone else says "You'll get used to it", run. Run like hell. You'll get used to dealing with it, but you won't get used to it.

Ah yes, almost forgot. The "dust". The "dust" wasn't normal dust I've dealt with everywhere else I've lived. This "dust" was black soot-like nasty stuff.I'm guessing it was a combination of tire particles and brake particles, with a scattering of diesel stuff. Whatever, whenever I dusted I didn't get a light gray on my rag, I got a dark black.

Moral of the story? don't buy a house next to a freeway or, corollary, by a busy street.

Re:I used to live by one

[Mashiki]

Moral of the story? don't buy a house next to a freeway or, corollary, by a busy street.

Good advice, but then again if you've lived near such all your life? You'll probably miss the sounds/noise. I live within 300m of the 401(busiest highway in north america), the noise doesn't bother me. When I go traveling, and have to rent motels/hotel/etc rooms, I try to aim for places that are within the same distance of the nearest big highway. I find it completely relaxing, same with when I was a kid. Round that out that I've either lived right on, or within 250m of one of the busiest rail lines in Ontario(CN main trunk) all my life as well? Even those 5min long, chugging diesels? You learn to ignore it, or wonder why you don't hear it. Odd thing is, when I was growing up you could always tell there was warmer weather coming, because the sound would be much clearer(winds from the south). It's kinda stuck with me over the last 30 years.

The dust though? Almost 100% in the last 20 years from tires or diesel particulate. Brakes have been semi-metalic or made from ceramics for over a decade as well. It actually used to be worse when brakes were metallic(asbestos), I was doing my apprenticeship when they were just about to phase out to semi. But if you think that dust is bad? You've never lived near an open pit mine, that's dust. Lived near a few in my day, one near Beachville, Ontario(used to be the largest open pit lime mine in the world). And near the open pit coal mines in Grande Cache, Alberta. The amount of dust you'd see in most places in a month? Easily a day, sometimes half a day if the wind was blowing right.

Re:This sounds familiar

[dgatwood]

The study corrected for differences in income.

That said, sleep disruption caused by traffic noise is, IMO, far more likely to be the cause of the increase in dementia than air pollution.

N 6.6M

[SETY]

The study tracked 6.6 million people. This is awesome. These are the type of studies we need, big data studies. Everyone is always worried about medical records, but when you have a single payer system there is less of a worry about that. Imagine what else they can discover from that dataset!

Re:must be the lead

[Strider-]

So local cathedral in Vancouver just underwent a major restoration where they replaced the roof. The church is located on one of the busiest intersection sin the city. As they did their work, and removed the old roof, they ran into the unanticipated problem of significant amounts of lead dust filtering down into the rest of the building. It was then that it dawned on them that the church had been sitting on the busiest intersection in the city for 100 years, and for a significant portion of those, vehicles had used leaded gasoline. The remediation of the lead added about 25% to the cost of the renovation.

No, it's reflexive - myself

[raymorris]

"I was looking for a house for me"?
No, "I was looking for a house for myself." It's reflexive.
Therefore "I was looking for a house for my fiance and myself."

An easy way to know: I=he, him=me, himself=myself

[raymorris]

Ps, if grammar terms like subject, object, and indirect object don't come natural to you, here's one way to distinguish I, me, and myself. Replace them with he, him, and himself. Like so:

Bob found a house for himself. Sounds fine.
Bob found a house for he. Doesn't sound right.
Bob found a house for him. Still not right, if "him" means Bob.

Himself is analogous to myself, so myself is correct.

There aren't that many urban areas in Canada

[Bruce66423]

You're joking aren't you? Most of the Canadian population lives in big cities - Toronto, Montreal and Vancouver all have over 2 million people in their metropolitan areas.

Pollutants or stress?

[Applehu Akbar]

The study doesn't seem to separate these two factors. We live near a busy intersection and used to notice traffic noise at night, when we sleep with the windows open. Several years ago the signal at the intersection was replaced by a roundabout. Suddenly it was really quiet at night, since most traffic just glides through. But by day when the traffic is heavy with tourists who don't get roundabout driving, there can be a lot of honking. When we're out on the paio at a time like this, road rage is a great form of rural theater.