Very hard to see how they can discount confounding correlates to diesel particulate and other PM10 and finer materials, brake dust &c.
Not that I don't think the science is good, I'm sure they do and the article says they do, but I struggle to see how you can isolate noise from particulate exposure: they'd have semi identical square law dropoff by distance and volume.
“The results are strengthened by the authors controlling for levels of traffic pollution, which was recently shown to be associated with dementia as well as other diseases.”
Skimming the article [0], it looks like they compared outcomes of people who lived closer to the road against people who lived farther away from the road, in the same building.
I think the idea is that people living in the same building should all have roughly the same particulate and pollution exposure, but people living on a road-facing side of the building will have more exposure to road noise. It's an extremely clever study design.
If the assumption is that people in the same building have the same exposure to pollution but differential exposure to noise based on distance, I would prefer that it were tested. I am sceptical that this is the case, as I would expect folk on the road facing side to be exposed to more particulates and pollution and noise.
That's a good point, and I didn't read far enough in the paper to see if they tested that assumption or not. It seems like they developed some kind of model of noise exposure as a function of elevation and proximity to the road, so it's possible they developed a similar model for pollution.
> 1. Electric trains wont generate diesel particulate, but will generate road noise.
They don't generate diesel particulate, by they do generate "other PM10 and finer particulate", from the brakes for example.
In Paris there's a lawsuit against the RATP (local transit authority) for particulate pollution inside the stations. [0]
There's also the fact that, at least in Paris, some metros are running on tires. For those that run on metal wheels and rails, some turns are quite sharp, and you can hear the screeching of the metal. This is likely to contribute to particulate pollution.
I suppose for overground trains, this is less of an issue.
Except road noise was associated with dementia and train noise wasn't, which suggests it's pollution related according to your (1)
The other problem is that people that live near noise are poorer. Did they control for wealth?
These epidemiological observational studies are so hard to take seriously. I get why so many of them are done though. It's a relatively lower effort way to get publications out the door, all you need is a dataset and a few days in python.
Of course they controlled for wealth (individual income, occupational status, highest attained education and neighbourhood socioeconomic status).
It's hard to take seriously HN commenters who assume people working outside software development are all idiots who need to be told how to do their job.
Epidemiological studies in general are flawed and hard to trust due to omitted variables that you don't know about, p-hacking and publication bias making it difficult or impossible to interpret causality. You say "of course" as if it's a foregone conclusion that the results should be trusted and the authors have done a good job, when the default should be disbelief and scepticism in this particular approach unless shown otherwise with unusually strong results. I only have a positive reaction and belief by default in large scale RCTs. Epidemiological studies have not earned the benefit of the doubt. At best they are indications of future experimental research directions, i.e. they are a means to an end.
I've worked in academic applied statistics research and seen how the cookie crumbles, it's not pretty, and yes there are groups and industries of people who may be individually intelligent but nevertheless act like idiots given the incentives they face to churn out low-effort publications. Search for "hegemony" or "Fuzzy neural net Dow Jones" in Google Scholar to see 140 IQ people mass produce drivel. Just because I am not trained in medicine doesn't mean I am not allowed to draw this conclusion, I have years of experience in statistics and know a bullshit application of these tools when I see it, and I don't appreciate appeals to authority or other arguments that try to invalidly shut down people's opinions without knowing why those opinions were formed in the first place.
The meaning of that saying is not literal; ”windy places” refers to unstable leadership in an organisation, with high-level executives often getting replaced.
In the region of Toulouse, France, "vent d'Autan", a strong wind that blows in that region is called "vent qui rend fou", the wind that drives people crazy. It is a bit of folk knowledge that seems to be verified: crimes rates are higher, people and animals are more agitated, ect...
And it is not the only occurrence where strong wind is associated with madness.
> Some settlers specifically spoke of the wind that rushed through the prairie, which was loud, forceful, and alien compared to what settlers had experienced in their former lives.
> A number of conditions such as acute hyperacusis can cause increased sensitivity to environmental sounds. These conditions can result from high stress and have been known to cause behavior consistent with descriptions of prairie madness such as depression, insomnia, and violent behavior.
> Wind direction appeared to be related to the patient's energy levels; these were significantly lower when the wind blew from the southeast. This effect could not be explained by other weather parameters. Decreases in energy in turn predicted increases in anxiety. The reverse effect was observed as well, with increases in anxiety predicting decreases in energy, indicating a positive feedback loop.
It seems plausible that wind from a specific direction through and across certain building structures could produce sound that is causing these variances.
> Valence enjoys a humid subtropical climate, whose main characteristic is an almost constant wind …. When it comes from the south, it usually announces the arrival of stormy disturbances. It is then called le vent du midi ou le vent des fous [the midi wind or the uncaring wind] because, for some people, it makes the atmosphere painful to bear, especially in the summer.
Impressive study... as someone who just bought a house 100m from large road, I'm just going to make myself read the last paragraph a few extra times:
> the best way to maintain brain health was to stay physically and mentally active, eat a healthy balanced diet, and keep your weight, cholesterol and blood pressure in check.
That works for car noises but not low frequency construction noises, which pass through almost anything. A room in a room seems to be the only solution there
I've recently looked into this, after I read this article
https://link.springer.com/article/10.1007/s00395-019-0753-y
. There are also noise isolating heavy curtains (FWIW the claim -20dBa). But the vibration stays and it might also have an effect
Install MERV #13+ and activated-carbon filters in your HVAC intakes, and ensure the fan runs even when the heat or a/c doesn't.
You don't need HEPA filters if the air circulates, because what doesn't get caught on one round probably gets caught on the next. Five rounds at 75% is as good as 99.9% once.
Placing tight filtration on the HVAC system can substantially reduce airflow over the coils and/or heat tubes, decreasing efficiency and possibly causing the system to malfunction.
The HVAC system just needs enough filtering to avoid impacting its operation. Any additional air particulate removal should be done separately.
Also a lot of particulate air pollution is generated inside the home. I bought a few sensors, and was quite astonished how loudly they all complained when I, for instance, fried bacon or cleaned the shower with off-the-shelf cleaning chemicals.
Not so big a difference as you might expect: bacon fat particles can be very small, and those that reach your alveolae are quite harmful, cumulatively.
Benzene you breathe enters your bloodstream, for a different sort of harm. You need a carbon filter to remove that from your air.
Fun fact: electric cars make larger, not smaller, road noises.
This is because wind and tire rolling noises take over any engine noise at > 15mph, and because electric vehicles are usually substantially larger and heavier than its counterparts.
Those whooosh noise of a car passing is mostly the sound of an 1.75t object rolling through displacing air.
Interesting. I'm definitely looking forward to electric buses and trucks though. Standing on the sidewalk when a bus accelerates next to you can be offensively loud.
A city in Germany (Osnabrueck) has switched all their buses to electric. They are much more silent, for sure.
I also don't feel like electric cars are more loud, at least at moderate speeds. I always had the impression that they're a lot more silent inside cities. Maybe on a highway that would be different, I can't say.
The biggest offenders of background noise are obviously trucks though.
Not where I lived, when I lived in a city. The worst offenders by far were motorcycles and cars which had aftermarket exhausts designed to be noisy. Much of the noise on roads is intentional.
Does the mass really affect the sound through the air? I'm sure that the shape and size of the vehicle will affect the wind noise, but I fail to see how the mass of the object directly affects the wind noise.
Tire noise, possibly, as the tire is holding that mass.
Just take a look at the actual weight of the Tesla Model 3.
It is listed between roundabout 1.600 kg and 1.800 kg which is absolutely in the ballpark of the two tons every other mid sized sedan weights. Example : Volkswagen model Passat: 1470kg - 1760kg.
At what distance? I live in the country, where there often is not a vehicle moving within a mile or so, and can guarantee that when cars do come nearby, it is the engines I hear, not the wind and tires.
I must have missed seeing the commercial launches of all those bigger than Chrysler C's bigger than Toyota Landcruiser's, bigger than Ford F150's etc that must have been selling like hotcakes.
That claim alone is enough to discount your entire comment.
It's good business, though. They want you to click on another link or ad on their site. If they even shared identifying information of the authors, you're more likely to go to google and search for it.
> These associations showed a general pattern of higher hazard ratios with higher noise exposure, but with a levelling off or even small declines in risk at higher noise levels
I wouldn't be surprised further study will show the last bit is due to earplugs at higher noise levels, resulting in a relative reduction in sleep disruption. Unless they also took earplug use into account already, then I'm genuinely curious what could be the reason
I hope this translates into stronger enforcement against very loud motorcycle exhaust. These seem designed to be unconscionably loud for the purpose of offending as many around as possible.
The most astonishing recent news about dementia surfaced in April, here on HN: A recent Tdap vaccination correlates very, very robustly with a 40% reduction in dementia risk (doi:10.1093/gerona/glab115).
Nobody knows how to interpret it. 40% is a huge effect size! (I doubt aspirin shows up as more effective against headache.) Is it the tetanus, the diphtheria, the pertussis antigen? Something else they put in the vaccine?
You can get a Tdap at any pharmacy, on demand. I did.
This isn't a randomized controlled trial, so I wouldn't put much stock in the results, although it should provide a catalyst for further study (if it hasn't already).
Fetishizing RCTs is a source of much harm in medical policy.
A correctly-designed RCT can give more confidence in a result, particularly to non-statisticians, but very large effect and cohort sizes should not be ignored. We could tell just from the topical statistics that smoking was a major cause of lung cancer and other harms, despite the tobacco industry insisting nothing was proven.
Typical RCTs with only a few hundred patients deliver much less resolution than this result. We do still need trials to home in on the molecular agent, but Tdap is already proven safe, and wise to stay current on, so it would be foolish to "wait and see". If it turns out Tdap (e.g.) protects only some patients from dementia, you are anyway safe from tetanus infection.
It is similar to the case where arginine supplements appear to cut epithelial tissue side effects of SARS-2 vaccines. It needs more study, but arginine is cheap and perfectly safe, so starting immediately to administer arginine supplements alongside vaccination is the prudent course.
Some RCTs even yield spurious results, as a consequence of poor design or execution, such as those lately promoted as showing that anti-depressants have no effect.
"Fetishizing" RCTs (i.e. realizing their importance) is a source of no harm, because it is the best design we have to determine whether some intervention actually helps people live longer or better. Effects from other kinds of studies should of course be weighed accordingly. Fetishizing observational/non-random studies is the source of harm. Taking the Tdap is very unlikely to hurt you, but calling this single study "astonishing" and implying that it indeed shows a 40% reduction in risk (it doesn't) is hyperbolic.
If you aren't astonished, you're not paying attention. This study was conducted over six years, on two independent cohorts, involving tens of thousands of patients.
A moment's consideration shows why an RCT to check tobacco smoke and lung cancer was impossible. We are nonetheless 100% confident, in the entire absence of an RCT, that smoking does directly cause lung cancer. The sort of fetishism you promote is exactly what delayed institutional recognition of the fact, by decades.
Ask any professional statistician about failure modes of RCTs. Be prepared to listen for a long time. Instead of worshipping blindly at the altar of RCTs, we should pay attention to what actual statisticians have to say about actual results.
Judea Pearl, in a recent book, "The Book of Why", provides a readable, in-depth exploration of statisticians' fundamental relationship with causuality, and the historical development of statisticians' decades-long loss of their ability to form conclusions from observational data, and their recent recovery. We are all healthier now that we know how and when we may confidently act on results of observational studies, without fetishism.
And yet, due to its design, it is still entirely plausible that there is no, or very little effect. We just don't know.
The reason institutions delayed smoking has nothing to do with RCTs and everything to do with regulatory capture and corruption. Even in the presence of RCTs (which wouldn't be ethical, of course) this still would've happened.
That RCTs have failure modes does not change the fact that they are the best we have in the face of confounding variables - they simply require good design. This claim about Tdap is not like smoking...we don't have the same understanding of the underlying biology nor the massive effect sizes from other studies.
I have read the Book of Why and Probabilistic Reasoning in Intelligent Systems. There is nothing within those books to indicate animus against well designed RCTs. Rather he advocates, as I already did, for intelligent combination of sometimes sparse RCTs with the large N of observational studies.
Your wholesale invention of "animus against well designed RCTs" anyway explains your impassioned defense of fetishizing RCTs. I have never encountered any such animus, and doubt you have, either.
You reveal that you missed that Pearl spells out circumstances where observational studies do suffice to demonstrate what you insist requires an RCT.
And, you show you missed the entire section on the historical events that led to your and others' continuing fetishization of RCTs as the only possible means to demonstrate causation, and their lack to make any such demonstration impossible, which you continue to insist upon, against reason.
Your late admission that RCTs may be poorly designed, and thus fail to demonstrate what they claim, contradicts your previous fetishistic insistence on RCTs' infallibility.
I was hiking once in my home rural area after they "terraformed" a highway through the mountains. The main thought in my mind was - it will never be quiet here again.
Interestingly I've heard the same thing said about hearing loss. They may or may not be connected. But I think the people here adding diesel and braking particulates into the equation are probably onto something.
Have they studied if air conditioner or fan sounds have a similar effect?
The negative health outcomes in this study correlate well with those found in lead poisonig studies. Enormous quantities of lead were deposited along our roadways over a period greater than 50 years. It would be very difficult to decouple "transport noise" from the lead pollution that is known to exist along those transport routes.
86 comments
[ 5.7 ms ] story [ 170 ms ] threadNot that I don't think the science is good, I'm sure they do and the article says they do, but I struggle to see how you can isolate noise from particulate exposure: they'd have semi identical square law dropoff by distance and volume.
“The results are strengthened by the authors controlling for levels of traffic pollution, which was recently shown to be associated with dementia as well as other diseases.”
I think the idea is that people living in the same building should all have roughly the same particulate and pollution exposure, but people living on a road-facing side of the building will have more exposure to road noise. It's an extremely clever study design.
0: https://www.bmj.com/content/374/bmj.n1954
1. Electric trains wont generate diesel particulate, but will generate road noise.
2. It's relatively straightforward to measure pollution and noise, so you can do analysis to try and separate them.
In many situations these would not be correlated exactly. For example, terrain, wind patterns, noise dampening structures, etc.
They don't generate diesel particulate, by they do generate "other PM10 and finer particulate", from the brakes for example.
In Paris there's a lawsuit against the RATP (local transit authority) for particulate pollution inside the stations. [0]
There's also the fact that, at least in Paris, some metros are running on tires. For those that run on metal wheels and rails, some turns are quite sharp, and you can hear the screeching of the metal. This is likely to contribute to particulate pollution.
I suppose for overground trains, this is less of an issue.
---
[0] https://www.rfi.fr/en/france/20210323-french-ngo-sues-paris-...
[1] https://en.wikipedia.org/wiki/Montreal_Metro#Design
Popcorn!
The other problem is that people that live near noise are poorer. Did they control for wealth?
These epidemiological observational studies are so hard to take seriously. I get why so many of them are done though. It's a relatively lower effort way to get publications out the door, all you need is a dataset and a few days in python.
It's hard to take seriously HN commenters who assume people working outside software development are all idiots who need to be told how to do their job.
I've worked in academic applied statistics research and seen how the cookie crumbles, it's not pretty, and yes there are groups and industries of people who may be individually intelligent but nevertheless act like idiots given the incentives they face to churn out low-effort publications. Search for "hegemony" or "Fuzzy neural net Dow Jones" in Google Scholar to see 140 IQ people mass produce drivel. Just because I am not trained in medicine doesn't mean I am not allowed to draw this conclusion, I have years of experience in statistics and know a bullshit application of these tools when I see it, and I don't appreciate appeals to authority or other arguments that try to invalidly shut down people's opinions without knowing why those opinions were formed in the first place.
In the region of Toulouse, France, "vent d'Autan", a strong wind that blows in that region is called "vent qui rend fou", the wind that drives people crazy. It is a bit of folk knowledge that seems to be verified: crimes rates are higher, people and animals are more agitated, ect...
And it is not the only occurrence where strong wind is associated with madness.
And I can attest that on Sundays, when the city is silent, that howling wind and the loose shutters banging make you feel strange indeed.
https://en.wikipedia.org/wiki/Prairie_madness
> Some settlers specifically spoke of the wind that rushed through the prairie, which was loud, forceful, and alien compared to what settlers had experienced in their former lives.
https://core.tdar.org/document/441632/the-wind-cries-mary-th...
> A number of conditions such as acute hyperacusis can cause increased sensitivity to environmental sounds. These conditions can result from high stress and have been known to cause behavior consistent with descriptions of prairie madness such as depression, insomnia, and violent behavior.
I also found this interesting case report:
https://casereports.bmj.com/content/2012/bcr-2012-006300.sho...
> Wind direction appeared to be related to the patient's energy levels; these were significantly lower when the wind blew from the southeast. This effect could not be explained by other weather parameters. Decreases in energy in turn predicted increases in anxiety. The reverse effect was observed as well, with increases in anxiety predicting decreases in energy, indicating a positive feedback loop.
It seems plausible that wind from a specific direction through and across certain building structures could produce sound that is causing these variances.
Mythbusters assemble!
https://en.wikipedia.org/wiki/Valence,_Drôme#Climate
> Valence enjoys a humid subtropical climate, whose main characteristic is an almost constant wind …. When it comes from the south, it usually announces the arrival of stormy disturbances. It is then called le vent du midi ou le vent des fous [the midi wind or the uncaring wind] because, for some people, it makes the atmosphere painful to bear, especially in the summer.
> the best way to maintain brain health was to stay physically and mentally active, eat a healthy balanced diet, and keep your weight, cholesterol and blood pressure in check.
In any case, noise isolation can make a huge difference.
You don't need HEPA filters if the air circulates, because what doesn't get caught on one round probably gets caught on the next. Five rounds at 75% is as good as 99.9% once.
The HVAC system just needs enough filtering to avoid impacting its operation. Any additional air particulate removal should be done separately.
Benzene you breathe enters your bloodstream, for a different sort of harm. You need a carbon filter to remove that from your air.
This is because wind and tire rolling noises take over any engine noise at > 15mph, and because electric vehicles are usually substantially larger and heavier than its counterparts.
Those whooosh noise of a car passing is mostly the sound of an 1.75t object rolling through displacing air.
I also don't feel like electric cars are more loud, at least at moderate speeds. I always had the impression that they're a lot more silent inside cities. Maybe on a highway that would be different, I can't say.
The biggest offenders of background noise are obviously trucks though.
You aren't wrong.
Tire noise, possibly, as the tire is holding that mass.
ICE + transmission + all the related cruft (cooling, battery, starter motor, fuel & pump) easily weigh a few hundred kilos.
An EV has a lot less components than a combusion car. So much so that they can add a second trunk where the heavy combusion engine normally sits.
One example: https://www.toi.no/getfile.php/1340825-1434373783/mmarkiv/Fo...
I must have missed seeing the commercial launches of all those bigger than Chrysler C's bigger than Toyota Landcruiser's, bigger than Ford F150's etc that must have been selling like hotcakes.
That claim alone is enough to discount your entire comment.
It's odd that the Guardian neither links to it, nor even names the researchers or their institution.
https://doi.org/10.1136/bmj.n1954
I wouldn't be surprised further study will show the last bit is due to earplugs at higher noise levels, resulting in a relative reduction in sleep disruption. Unless they also took earplug use into account already, then I'm genuinely curious what could be the reason
https://duckduckgo.com/?q=harley+davidson+remove+baffles
Nobody knows how to interpret it. 40% is a huge effect size! (I doubt aspirin shows up as more effective against headache.) Is it the tetanus, the diphtheria, the pertussis antigen? Something else they put in the vaccine?
You can get a Tdap at any pharmacy, on demand. I did.
A correctly-designed RCT can give more confidence in a result, particularly to non-statisticians, but very large effect and cohort sizes should not be ignored. We could tell just from the topical statistics that smoking was a major cause of lung cancer and other harms, despite the tobacco industry insisting nothing was proven.
Typical RCTs with only a few hundred patients deliver much less resolution than this result. We do still need trials to home in on the molecular agent, but Tdap is already proven safe, and wise to stay current on, so it would be foolish to "wait and see". If it turns out Tdap (e.g.) protects only some patients from dementia, you are anyway safe from tetanus infection.
It is similar to the case where arginine supplements appear to cut epithelial tissue side effects of SARS-2 vaccines. It needs more study, but arginine is cheap and perfectly safe, so starting immediately to administer arginine supplements alongside vaccination is the prudent course.
Some RCTs even yield spurious results, as a consequence of poor design or execution, such as those lately promoted as showing that anti-depressants have no effect.
Fetishism should have no place in medicine.
A moment's consideration shows why an RCT to check tobacco smoke and lung cancer was impossible. We are nonetheless 100% confident, in the entire absence of an RCT, that smoking does directly cause lung cancer. The sort of fetishism you promote is exactly what delayed institutional recognition of the fact, by decades.
Ask any professional statistician about failure modes of RCTs. Be prepared to listen for a long time. Instead of worshipping blindly at the altar of RCTs, we should pay attention to what actual statisticians have to say about actual results.
Judea Pearl, in a recent book, "The Book of Why", provides a readable, in-depth exploration of statisticians' fundamental relationship with causuality, and the historical development of statisticians' decades-long loss of their ability to form conclusions from observational data, and their recent recovery. We are all healthier now that we know how and when we may confidently act on results of observational studies, without fetishism.
The reason institutions delayed smoking has nothing to do with RCTs and everything to do with regulatory capture and corruption. Even in the presence of RCTs (which wouldn't be ethical, of course) this still would've happened.
That RCTs have failure modes does not change the fact that they are the best we have in the face of confounding variables - they simply require good design. This claim about Tdap is not like smoking...we don't have the same understanding of the underlying biology nor the massive effect sizes from other studies.
I have read the Book of Why and Probabilistic Reasoning in Intelligent Systems. There is nothing within those books to indicate animus against well designed RCTs. Rather he advocates, as I already did, for intelligent combination of sometimes sparse RCTs with the large N of observational studies.
You reveal that you missed that Pearl spells out circumstances where observational studies do suffice to demonstrate what you insist requires an RCT.
And, you show you missed the entire section on the historical events that led to your and others' continuing fetishization of RCTs as the only possible means to demonstrate causation, and their lack to make any such demonstration impossible, which you continue to insist upon, against reason.
Your late admission that RCTs may be poorly designed, and thus fail to demonstrate what they claim, contradicts your previous fetishistic insistence on RCTs' infallibility.
Where is my nobel?
Have they studied if air conditioner or fan sounds have a similar effect?
https://en.wikipedia.org/wiki/Tetraethyllead https://www.pbs.org/wgbh/nova/article/herbert-needleman/ https://en.wikipedia.org/wiki/Thomas_Midgley_Jr.