Very interesting
Long-term exposure to air pollution raises the risk of depression, according to a pair of new studies published in the JAMA network of scientific journals.
www.sciencealert.com
"They studied a group of nearly 390,000 people, mostly in Britain, over a period of 11 years and found there was an increased risk for depression and anxiety even at pollution levels below UK air quality standards."
Studies like this one and the ones they cite as related suffer from the problem that they are looking for associations - correlations in fact.
I am certain that you are familiar with the old saying, 'correlation is not causation.'
Dealing with that issue is a fundamental part of any course in 'research methods and statistics'.
The fact that two things seem to fit together in the data does not mean that one caused the other. For example - there is a robust correlation in the UK between drowning and sales of ice cream. Drownings go up as ice cream sales rise. Would anyone claim that the sales of a confectionery product caused the drownings? Of course not. In that case there is an obvious external factor which is much more likely to account for the increase in drownings. People in the UK rush to spend more time by water bodies when the weather is hot and sunny and also happen to buy more ice cream at these times. It is the proximity of lots of people - especially the young to bodies of water which leads to the drownings.
This is just an illustrative example of why studies of correlation which almost all of these ill health / air quality papers claims depend on and this is why I object to their use in building up fantastical claims related to air quality issues - especially when the air quality of the UK is VASTLY better than it has ever been since the Industrial Revolution - an objective fact - which I have repeatedly linked to with government web site graphs and data.
I do not disagree at all that heavy air pollution is both unpleasant and harmful. I am of an age to remember when most homes in the city of my birth were heated by coal fires burning filthy bituminous coal which caused a heavy stink of the chemical byproducts of low temperature coal burning. I remember that most of the grand public buildings built of sandstone were black with soot - an obnoxious chemical cocktail of poisonous compounds. NONE of that exists now, but we are constantly bombarded by exaggerated claims which are easily knocked down, and can be demonstrated as ridiculous by simply looking at the graphs I have shown here which make it clear that particulate pollution has been vastly reduced since even the 1970s - eighty percent reductions in particulates and similar in Nitrogen Oxides. This is an entirely different country to the one I lived in sixty odd years ago as far as air quality is concerned.
The claim in the article linked to, suggests that air pollution is related to depression. This is ridiculous. The writer points out that -
""Socioeconomically disadvantaged individuals were observed to be at a much higher risk of late-life depression in this study," they said. "They are simultaneously exposed to both social stress and poor environmental conditions, including air pollution."
Indeed, they may be, but WHICH of the factors mentioned CAUSED their increased tendency to depression? Shortage of money? Social stress? Poor environmental conditions?
Also though; the writer does not mention probably the most damaging blight on the lives of socio-economically disadvantaged people -
low levels of education and absolutely terrible life-style habits, such as bad diet, high incidence of toxic habits such as smoking, alcohol and drug abuse and chaotic behaviour. THESE kinds of issues are vastly more damaging than the one picked out for attention.
This is absolutely terrible research. And a useless article if you want to know what caused the depression or other health issues. It ignores the most likely causes and focuses on one of the least likely ones.
Coming back to the core of my issues with this kind of material - you can only attribute causation by controlling for all the variables. This is what experiments do. The researcher either removes or controls for all the variables, and this is very difficult to do when we are talking about multi faceted problems and doing so over the lifetime of participants . Only if you do this, can you then assert with confidence, that increased consumption of ice cream either does or does not cause an increase in drowning, or that low levels of air pollution create depression.
I am reluctant to get drawn further into this discussion because it has been shown to be entirely fruitless. There are people here who have a religious attachment to what amounts to a doctrine. It has nothing to do with actual data and well conducted research. They spurn the opinions of Dr Spiegelhalter, the emeritus professor of statistics at Cambridge University that the claims that forty thousand people a year in Britain die prematurely because of air pollution are pretty much baseless, so what can I say that will convince them. might as well go to Salt Lake City and tell the prophets of Mormonism that Joseph Smith was a con man.
