Killer Commercial Airlines

Chemtrails are all over the internet, and purported to be part of a government conspiracy to poison or control populations. This is complete psuedoscience and fear mongering debunked in skeptoid episode 27. Major news outlets are reporting today that science has produced a link with jet aircraft and heart attacks. No it is not a chemtrail story, it is another example of thrill science publishing and reporting.

 “Exposure to Aircraft noise may increase the risk of hospitalizations for heart problems“. When I first read the story, I immediately assumed reporter error and twisted exaggeration. Not at all. It is the BMJ that is at fault here.

I am dismayed by the conclusions of the actual study. I have to give the media a partial pass because analyzing the complicated double speak is difficult. The conclusions of this study are on such shaky ground that my initial impression is that this is one of the well known BMJ “Joke” studies that it publishes annually in the Christmas holiday edition. As far as I can tell the paper seems serious and not a spoof.

The title of the paper is”Aircraft noise and cardiovascular disease near Heathrow airport in London: small area study“. It proposes that having controlled for the confounding factors as best they can, the authors see a statistically significant link between exposure to aircraft noise; coronary artery disease, stroke and mortality.

My Opinion, I am stunned that this pile of tripe got published. It is a very nice statistical exercise but what it really says about anything is unclear. There is so much wrong methodologically that I hope the conclusions from this data cannot be serious. It may have been done on purpose. Either to expose poor science reporting, study poor science reporting, or to try to drum up public support financially for their research. That can explain the author’s fail. It completely escapes me why the BMJ would publish it as a serious paper.

Here are a few of the major methodological error highlights making the stated conclusion impossible to determine.

  1. They retroactively took chart data from hospital admissions and compared it to airline noise plots based on time of day and location. The data controlled for air pollution, and some patient demographics. It did not remove exclude or analyze any other noise sources for the patients.  Meaning that the authors in metropolitan London assumed that all other noise sources were irrelevant compared to airline noise.
  2. They included no data on the following confounding cardiovascular risk factors: Body mass index, serum lipid profile, family history, exercise tolerance or frequency, employment, interior personal environment(IE:smoke filled lounge), driving or not, traffic or not, amount of sleep, psychiatric stressors, caffeine intake, alcohol or illicit drug use(there is more for brevity I will stop). What they did they control for? “adjusted for age, sex, ethnicity, deprivation, and a smoking proxy (lung cancer mortality) using a Poisson regression model”
  3. They used a statistical expansion model increase actual data points to more than they collected. It is a statistically valid technique but not for this type of study.
  4. They even noted that their population was heavily laden with biases, loading a group of distinct ethnic groups into one group “south Asian”
  5. For the premier fail of the study “We were able to adjust at small area level for ethnicity, deprivation, and a smoking proxy (and additionally for particulate air pollution and road traffic noise for a subset of 2.6 million people), but we did not have access to individual level information on confounders such as smoking; therefore results at the area level may not be applicable to individuals (ecological fallacy). ” Meaning they did not know if they were smokers or not. They averaged it out based on population grouping. I would term that a major confounding factor. How can you possible consider cardiovascular mortality factors without knowing if the patient is an active smoker? Answer: YOU CAN’T!

Just a stunning pile of research fail. This study is so loose that I am not even sure you can depend on any of the statistical findings. It is absolutely false to say that they can correlate airline noise with heart disease. It would be like publishing a paper about car accidents and drinking water. Primarily concluding in that paper that drinking a glass water in the 72 hours before a car accident causes it.

Utter and complete rubbish, shame on the BMJ. The study is slick and well done I can only fault the reporting to a point. If science reporters just called anyone with medical expertise and asked for a medical opinion on this study it wouldn’t be the lead medical story for the day. That is also probably why media outlets don’t do that.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: