Just like to caution–there are a million ways to do bad epidemiology. Did the study correct for race and class? It’s well known that certain segments of society are more prone to asthma. I noticed this was a Southern Californian study; is it extrapolable to other air quality districts? etc etc.

Finally, not to minimize it, but if there’s one organ in the human body that’s overengineered, it’s the lungs. It’s rare that lung capacity is really a limiting factor in day-to-day life, unless you really go out of your way to destroy it (i.e. smoking) or have other conditions. If you’re pretty normal, you’re going to die of cancer, heart disease or stroke/diabetes/kidney failure, not lung disease.

Geez, David, you and I are just destined to butt heads.

As an epidemiologist, I agree that there is certainly some bad epidemiology out there. But I think a million would be a high estimate, and the Lancet continues to enforce one of the most rigorous peer review processes in academic publishing.

And indeed, the Gauderman study employed a longitudinal design with a big sample and annual data points. The analysis controlled for race, socioeconomic status, smoking, maternal smoking, previously diagnosed asthma, pets, and a host of other variables.

Also, this isn’t the only study to report this effect. The connection between proximity to freeway traffic and decreased lung function has been pretty firmly established. Gauderman et al. is remarkable only because it is such a rigorous study.

There is some evidence that the effect is variable according to genetic and susceptibility factors, but some effect has been observed across ethnicities, genders, socioeconomic status, etc. In other words, growing up next to a freeway decreases lung function for everyone, but perhaps for some more than others.

And it’s not just lung function either. Emerging evidence shows an alarming correlation between leukemia and proximity to freeway traffic, likely due to exposure to benzene and airborne hydrocarbons.

And no, human beings certainly cannot afford decreased lung function. About 5,000 Americans die every year just from asthma. One in five pediatric ER visits is asthma-related. About 15 percent of lung cancer diagnoses are in nonsmokers. And decreased lung function is a major risk factor for cardiovascular disease.

This is a no-brainer, David. If you have children, do not buy or rent within a quarter mile of a freeway.

I work at a facility that uses Ozone as a part of our production process, so we have toxic monitors that alarm and cause evacuation when the levels indicate a toxic leak; we are also about a half mile from Highway 17 / 880. During the summer, we regularly experience false alarms due to freeway traffic; ie, even at this distance the freeway is producing levels above what is regarded as a threat to adult health.
If I were you, I’d opt for the full mile distance.

The Lancet has the most “rigorous peer-review process”??? Surely you jest–just like that 600,000+ Iraqis “killed,” right?

Anyway, I wasn’t saying it was a bad study; I hadn’t read it in its entirety. I was pointing out the usual factors in the multiple bad ways to do epidemiology. Your profession, as I’m sure you know, works in a field where it is EXTREMELY difficult to run real experiments (where you use a control, have a disprovable hypothesis, etc). Therefore, in order to have a truly rigorous study, you have to do “extra work” to make sure your findings are supported by the evidence.

This isn’t asthma. As you point out, this is lung function. This also isn’t lung cancer, which certainly does hit non-smokers, but in non-smokers, there is much evidence that it’s a different disease with a better prognosis. Cancer is a disease of old age, not many are caused by the environment.

5,000 deaths per year from asthma are certainly a tragedy. About 600,000 people die each year from heart disease and a similar number from cancer.

As for relating to heart disease, is it causation or simply coincidence? My bet is the latter.

The limits to exercise are not lung capacity, it is heart/blood delivery to muscle.

Another good question would be are some freeways different–580 and 13 don’t have much truck traffic; is it diesel trucks that are to blame or general particulates? etc. etc.

I did scan the study and noted that 34% of kids moved and 11% dropped out each year. Not too helpful, that.

This was a good post Tracey.

We are looking at Montclair in the OAK hills.

Something that is coming dead ahead however, is all the backed up inventory from the last 1-2 years. This will show up on the market over the next 6 weeks. We have targeted 2009 for our purchase, as I think you will finally get a meaningful price correction that’s very broad based in the Bay Area this year.

Here is a sign of how much the market has shifted already, from the Q4 price peak of 2006–a quality 3/2 on the Berkeley flats for 550K.

http://www.millsteinassociates.com/1005Hearst/1005Hearst.htm

This probably isn’t the forum for a quickly broadening debate on epidemiology and health science, but I would like to make a few quick points.

The 2004 and 2006 Iraqi mortality studies published in the Lancet, while certainly inconvenient to the Bush Administration, a number of American and British politicians, and various radio talk show hosts, have been almost uniformly endorsed by epidemiologists and statisticians around the world. In fact, Les Roberts, one of the studies’ authors, was the keynote speaker at the American Statistical Association’s Joint Statistical Meeting last year. Subsequent re-analyses of the data that Roberts and colleagues collected have shown wider confidence intervals, but similar magnitudes. It’s certainly difficult to face the magnitude of the disaster in Iraq, but these were solid, rigorous studies.

Yes, good epidemiology requires “extra work.” Gauderman and colleagues did eight years of “extra work.” Besides, the negative pulmonary effect of freeway proximity isn’t based on this single study, but a large body of extant evidence collected over the last two decades all over the world.

Decreased lung function directly contributes to the development of asthma in children. But I mentioned asthma and lung cancer and cardiovascular disease because you had made the somewhat fantastical assertion that the lungs are “overengineered,” and that human beings can afford a little decreased lung function.

Do you really want to bet that the co-morbidity of cardiovascular disease and decreased lung function is a “coincidence”? I’d take that bet in a second, as would any cardiologist who’s been trained in the last 30 years. That’s why it’s called a “major risk factor.”

What you’re saying about lung capacity is just physiologically counterfactual. Try breathing very shallowly and see how quickly you get dizzy.

And an 11% drop-out rate is a little high, but not unusual for an urban cohort. There are ways to construct a regression model that will largely compensate.

Sorry for high-jacking your blog, Tracey.

Well, I am thrilled to have unwittingly sparked off such an erudite debate. No, Toady, I mind not one iota if we have veered off message. I have learned so much from your fascinating exchange with David.
Red: A very interesting contribution. It makes you think more should be written about this patently important subject. Thank you.
SurveyKid: Can you explain exactly what you mean by “backed up inventory”? I’m intrigued.

Hi Tracey,

Backed up inventory, or hidden inventory, is a phenomenon that you see in housing recessions–once you have completed at least one full selling season (Spring to Spring) and there’s been no price recovery. What happens is that each subsequent Spring, all these homeowners who pulled their listing last year in frustration at not “getting their asking price”, put their home back on the market again. This hidden supply then merges with new supply, like the Santa Monica Freeway meeting the 405 at rush hour.

The Bay Area now has at least one selling cycle’s worth of backed-up inventory. Other cities like Boston have two years worth. And a city like San Diego is working on its third.

I remember living in Los Angeles in the 1989-1993 period. Every late Winter there would be a small stabilization of prices, and then this massive amount of supply would pour onto the market. Realtors also refer to this middle stage of a housing recession as an Iceberg market, where the current “supply” you see on offer is only the tip of the iceberg of what would be for sale.

If you look at the recent DQ numbers, you basically see an almost sieze-up in transactions. That’s the classic over-Wintering set up to a huge amount of supply that will pour onto the market soon.

Unless of course I am wrong. (ho ho). I can only call it, like I see it.

SurveyKid: Very interesting. If you’re right I should have some more choice coming my way. At the moment finding any homes for sale in my ideal neighborhoods is like drawing water from a stone. Thanks for the explanation.

SurveyKid is right about seller’s behavior during the SoCal R.E. bust in the ’90’s.

I wish I could find the powerpoint by the UCLA R.E. prof. it documents this quite well, along with the boom extending from good ‘hoods’ to marginal ones (with the marginal ones increasing by the most %) and the reverse occurring during the bust.

PS. Widen the confidence interval wide enough, and your “finding” is useless.

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