Seth's Blog

For a long time it’s been clear that living on a farm protects children against asthma (compared to city life). A new study, done in Germany, tried to go a little further than that: to ask if it was microbial exposure that made the difference. Non-American scientists have been far more interested in the environmental causes of disease than American scientists.

They measured microbial exposure by studying mattress dust. One branch of the study used DNA techniques to measure microbial diversity of the dust; the other branch measured microbial diversity by seeing how many microbes could be cultured from the dust.

They found the usual farm/city difference in asthma: The city kids had roughly twice as much. They found the expected farm/city difference in microbial diversity of mattress dust: For a given species of bacteria or fungi, there was roughly twice as much chance of finding it in the farm dust.

Did the microbial difference explain the asthma difference? To find out they corrected for the farm difference. I think this means they looked within the farm kids to see if in this restricted group there was a microbial diversity/asthma risk correlation. In one branch of the study, there was a significant correlation. In the other branch, the correlation was nearly significant.

In all, the results support the idea that differences in microbial exposure explain the farm/city asthma difference. The biggest strength of this study is that they gathered useful evidence related to a major problem (asthma). The biggest weakness is how difficult it was. It involved about 15,000 kids and probably cost more than a million dollars.

Thanks to Aaron Blaisdell.

I highly recommend this editorial by Cory Doctorow about the dangers of allowing a small number of people — such as big companies — to control how everyone’s computer, smart phone, etc., operates. I especially like his conclusion, modeled on Isaac Asimov’s Three Laws of Robotics:

But we’ll only arrive at those solutions once we stop reflexively demanding limits on the general functionality of a PC and a network – and the sooner we do, the sooner we’ll legitimize a technology world whose first rule is “Obey your owner” and whose second rule is “Protect your owner’s interests”.

In case it isn’t obvious, self-experimentation and personal science increase your control of your body, just as Doctorow wants each person to control the technology they own. Without self-experimentation and personal science — and their ability to solve health problems in a way best for you — you give control over your body to doctors, drug companies, medical school professors, nutritionists, alternative-medicine advocates, and many others whose interests differ from yours. Often the difference is large — drug companies prefer expensive dangerous solutions to cheap safe ones.

Felix Salomon argues that fancy restaurants often manage to make their food a Veblen good — something that becomes more desirable when the price goes up. Restaurant food is a way to show off your wealth, in other words. (more…)

The media in China are government-controlled. There is a 30-minute newscast every day at 7:00 pm. A friend described it to me like this:

First 10 minutes: Government officials doing their jobs.

Middle 10 minutes: Chinese people being happy. Sports, food, achievements.

Final 10 minutes: People in other countries suffering.

Robert Delaney is a geologist who does environmental cleanup in Michigan. While cleaning up an abandoned military base, he found remarkably high contamination by a chemical called PFOS. He had been wondering what causes autism. He came across a rodent study that found that the combination of PFOS and ultrasound was much more damaging to the nervous system than either alone. (See also this study.) He remembered that study when he read my posts about ultrasound and autism. He wrote to me: (more…)