Study finds link between hardened arteries, living near L.A. freeway

[marmar]

from the Los Angeles Times:



Study finds link between hardened arteries, living near L.A. freeway
February 14, 2010 | 6:57 am

Los Angeles residents living near freeways experience a hardening of the arteries that leads to heart disease and strokes at twice the rate of those who live farther away, a study has found.

The paper is the first to link automobile and truck exhaust to the progression of atherosclerosis -- or the thickening of artery walls -- in humans. The study was conducted by researchers from USC and UC Berkeley, joined by colleagues in Spain and Switzerland, and was published this week in the journal PloS ONE.

Researchers used ultrasound to measure the wall thickness of the carotid artery in 1,483 people who lived within 100 meters, or 328 feet, of Los Angeles freeways. Taking measurements every six months for three years, they correlated their findings with levels of outdoor particulates -- the toxic dust that spews from tailpipes -- at the residents’ homes.

They found that artery wall thickness accelerated annually by 5.5 micrometers -- one-twentieth the thickness of a human hair -- or more than twice the average progression in study participants.

The findings show, according to co-author Howard N. Hodis, director of the Atherosclerosis Research Unit at USC’s Keck School of Medicine, “that environmental factors may play a larger role in the risk for cardiovascular disease than previously suspected.”
Read the full story at Greenspace, The Times' environment blog.

-- Margot Roosevelt



http://latimesblogs.latimes.com/lanow/2010/02/study-finds-link-between-hardened-arteries-living-near-la-freeway.html

[WhiteTara]

1. I wonder if it has to do with the noise

as well as the exhaust emission.

[Chemisse]

2. Interesting!

My only criticism though, is that those people in LA who live close to the Freeway may be different in other ways. Does the property near the freeways have a lower value because of this proximity, so more likely to have poorer people or people of a certain ethnicity living there? If that is the case, other factors, like eating habits, genetic factors, percent of people there who smoke, etc. could be contributing to the disease.

Perhaps they considered all that in the study, but no details are included in the articles.

Criticism aside, I am inclined to agree with their conclusion, and hope such studies can further spur efforts to reduce pollution.

[left coaster]

6. Bingo!

That's exactly what I was thinking.. this kind of study is only focusing in on one aspect: the inhaled pollution factor. I myself live in a working/middle class neighborhood, located one block from L.A.'s 60 FWY.. just to give you an idea on the going rate of homes in my neighborhood, right now, post real estate bust, houses like mine have been selling for around $275,000 to $300,000).

Noise pollution is a major physical and mental stressor here, it's a 24 hour a day/7 day a week, non-stop roar..the county just erected a sound wall in the fall of 2009, and it's helped dampen the traffic noise..though there are still several points along the wall that were left open, so it's in no way an ideal fix.. IT'S STILL VERY LOUD OUTSIDE.. There's also the other factors that may contribute to those hardened arteries, like diet, lifestyle/work related, that are specific to individuals who live in working/middle class neighborhoods that border freeways.

[freeplessinseattle]

9. yes, I'd like them to study Seattle, too!

I live maybe 50 ft. from the freeway, seriously-I used to be able to see people's facial expressions before the sound wall was put up last year. Was great for campaign and other signs for awhile.

Seattle may have different demographics than the LA freeway zone dwellers-directly on the other side of the highway from me are the million dollar range homes with killer views, (and my neighborhood being hilly as well also has higher priced view properties). Not really worth the money in my opinion, sound rises and I've been told being on the balcony isn't really relaxing and you can't hear conversation very well.

[Chemisse]

12. Noise! I didn't even think of that.

Loud and constant noise is a stressor, and certainly stress is linked to heart disease.

"24 hour a day/7 day a week, non-stop roar"

Wow.

[Gormy Cuss]

8. That's a good point. The researchers used randomized trials which should mitigate that factor.

What's interesting to me is that they found this across heterogeneous groups. It's also worth noting that the authors are clear that the findings aren't strong enough to do more than suggest a link and are not generalizable.

Background

Cross-sectional studies suggest an association between exposure to ambient air pollution and atherosclerosis. We investigated the association between outdoor air quality and progression of subclinical atherosclerosis (common carotid artery intima-media thickness, CIMT).

Methodology/Principal Findings

We examined data from five double-blind randomized trials that assessed effects of various treatments on the change in CIMT. The trials were conducted in the Los Angeles area. Spatial models and land-use data were used to estimate the home outdoor mean concentration of particulate matter up to 2.5 micrometer in diameter (PM2.5), and to classify residence by proximity to traffic-related pollution (within 100 m of highways). PM2.5 and traffic proximity were positively associated with CIMT progression. Adjusted coefficients were larger than crude associations, not sensitive to modelling specifications, and statistically significant for highway proximity while of borderline significance for PM2.5 (P = 0.08). Annual CIMT progression among those living within 100 m of a highway was accelerated (5.5 micrometers/yr <95%CI: 0.13–10.79; p = 0.04>) or more than twice the population mean progression. For PM2.5, coefficients were positive as well, reaching statistical significance in the socially disadvantaged; in subjects reporting lipid lowering treatment at baseline; among participants receiving on-trial treatments; and among the pool of four out of the five trials.

Conclusion

Consistent with cross-sectional findings and animal studies, this is the first study to report an association between exposure to air pollution and the progression of atherosclerosis – indicated with CIMT change – in humans. Ostensibly, our results suggest that air pollution may contribute to the acceleration of cardiovascular disease development – the main causes of morbidity and mortality in many countries. However, the heterogeneity of the volunteering populations across the five trials, the limited sample size within trials and other relevant subgroups, and the fact that some key findings reached statistical significance in subgroups rather than the sample precludes generalizations to the general population.

http://www.plosone.org/article/info%3Adoi/10.1371/journal.pone.0009096

[Nikki Stone1]

10. Thanks for putting up the methodology. The pollution seems to be the culprit.

...

[Chemisse]

11. Oh good for you! You dug a little deeper to fund the details :) - nt

[Luminous Animal]

3. We need to ban driving near people.

[justabob]

4. I'd like to see the results from different cities + highways

to compare.

As someone else said, there are a lot of factors to consider, but it is not surprising at all that exhaust would have detrimental effects like this.

[Tikki]

5. Easy access to Fast Food joints.....

Tikki

[madokie]

7. I have that

Of course I don't live near a big ass hyway either. The doc says early sweets, cigarettes and liquor all played a role in mine. Actually he doesn't have a clue. I spent a week in the hospital with a DVT and yet I have good cholesterol numbers and my docs just shrugs his shoulders at that.

[Hannah Bell]

13. duh. much more important than second-hand smoke, for example.

[surrealAmerican]

14. We could have a boatload of evidence ...

... that cars are killing us and reducing our quality of life, and it wouldn't make a bit of difference. The whole country would need to be redesigned to get away from our dependence on cars.
Not that we shouldn't try to do just that, but it's going to take a very long time.