Car fumes 'raise heart attack risk for six-hour window'

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Car fumes 'raise heart attack risk for six-hour window'
Interesting BMJ work reported on BBC website



(link: http://www.bbc.co.uk/news/health-14978027 )

QUOTE:

Breathing in heavy traffic fumes can trigger a heart attack, say UK experts.

Heart attack risk is raised for about six hours post-exposure and goes down again after that, researchers found.

They say in the British Medical Journal that pollution probably hastens rather than directly cause attacks.

But repeated exposure is still bad for health, they say, substantially shortening life expectancy, and so the advice to people remains the same - avoid as far as is possible.

Prof Jeremy Pearson, associate medical director at the British Heart Foundation, which co-funded the study, said: "This large-scale study shows conclusively that your risk of having a heart attack goes up temporarily, for around six hours, after breathing in higher levels of vehicle exhaust.

"We know that pollution can have a major effect on your heart health, possibly because it can 'thicken' the blood to make it more likely to clot, putting you at higher risk of a heart attack.

"Our advice to patients remains the same - if you've been diagnosed with heart disease, try to avoid spending long periods outside in areas where there are likely to be high traffic pollution levels, such as on or near busy roads."

The research looked at the medical records of almost 80,000 heart attack patients in England and Wales, cross-referencing these details with air pollution data.

This enabled the investigators to plot hourly levels of air pollution (PM10, ozone, CO, NO2, and SO2) against onset of heart attack symptoms and see if there was any link.

Higher levels of air pollution did appear to be linked with onset of a heart attack lasting for six hours after exposure.

After this time frame, risk went back down again.

Krishnan Bhaskaran from the London School of Hygiene and Tropical Medicine, who led the research, said the findings suggested that pollution was not a major contributing factor to heart attacks.

For example, being exposed to a spell of medium-level rather than low-level pollution would raise heart attack risk by 5%, by his calculations.

"If anything, it looks like it brings heart attack forward by a few hours. These are cardiac events that probably would have happened anyway."

But he said the findings should not detract from the fact that chronic exposure to air pollution was hazardous to health.

Prof Pearson from the BHF agrees: "Unhealthy diets and smoking etc are much bigger heart attack risk factors, but car fumes are the cream on the cake that can tip you over."
 
I wonder which media outlet will now use this to 'prove' cycling is bad for your health, ignoring the fact all road users - in vehicles or on foot - will be breathing in these fumes. And who is going to have the higher baseline fitness and hence less risk of heart disease to begin with? fat van man or regular cyclist?
 
It doesn't reference this to cyclists though doesn't it?


And I thought it was said that the person sat inside the car gets through more pollution than a cyclist?
 

400bhp

Guru
How do they know it isn't the stress of sitting in a car in a traffic jam that causes the increased risk?

"We know that pollution can have a major effect on your heart health, possibly because it can 'thicken' the blood to make it more likely to clot, putting you at higher risk of a heart attack.
 
Here you go. An article in the Mail Online about this very piece of research. No mention of cyclists at all but wait...what is the first picture used to illustrate the article? Yep you guessed it - a mask wearing cyclist!

Then there is a picture of a defibrillator from a patient POV (note: if you can see a defibrillator about to be used on your good self you really don't need one). Defibrillators are not used to treat 'heart attacks' (Myocardial Infarction) but very fast or chaotic heart rhyhtms (tachyarrythmias) when the heart has effectively stopped pumping (Cardiac Arrest). Sometimes a Myocardial Infarction can cause an abnormal rhythm and so require a defibrillator but usually this is not required.

Just dramatic and inaccurate images used to spice up the article in the name of journalism I suppose. But the problem IMO is that some people will glance at this piece of 'journalism' and make the connection that cycling in traffic fumes will lead to cardiac arrest and so the image of cycling being dangerous is further propogated.

Makes me weep it does.

:-((
 
It doesn't reference this to cyclists though doesn't it?
10.jpg
It has a photo of a cyclist wearing a face mask. The connection is therefore made between cycling and the headline. My point is there is no reference to cyclists at all in the research or the article. Why has this image been used then rather than say one of a fat man, smoking a fag, sat at the wheel of a stationery vehicle in a traffic jam?
 

the snail

Guru
Location
Chippenham
My experience supports their findings. I went to a stop smoking clinic earlier this year, and had my blood CO tested regularly. They said it was a bit high, which was put down to my cycling. When I took a busier more congested route the readings were higher, 8ppm vs 5ppm IIRC, although when I smoked it was 24ppm. This was in Chippenham outside rush hour, so in a city rush hour I would guess the amounts could be a lot higher. There was certainly no suggestion that I shouldn't cycle though! I think the conclusion I'd draw from this research is that pollution levels need to be reduced, maybe there should be a limit on emissions in built up areas.
 
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