March 27, 2019

Air pollution is BAD for you -- particularly your heart -- EU study

One imagines that it is bad.  But how bad?  The article below purports to tell us.  And their conclusions  are a reasonable commentary on their results.  An equally reasonable conclusion would be that the effects of air pollution on health are totally trivial no non-existent.  

The numbers tell it best. After using all sorts of clever statistics to get the numbers up, they found that 8.79 MILLION deaths worldwide could be attributed to air pollution.   That sounds a lot, does it not?  That figure is however a mindless extrapolation.  You just have to note that the world's current estimated population is 7.7 BILLION to see what is going on.  What they actually found -- if you reverse their multiplication -- is that just over ONE PERCENT of all deaths are attributable to air pollution

Is that significant or trivial?  I will leave it for readers to judge.  Suffice it to say that if we wanted to work on preventing things that lead to premature death, air pollution would be a bottom priority.

But it gets worse than that.  The study below is a type of meta-analysis.  The authors appear to have taken every existing study they could find that estimates deaths from pollution and used those existing findings as their source of data.  But that is extraordinarily naive.  It is the antithesis of good scientific practice.  A meta-analysis should be highly selective, using only the best controlled of prior studies.  And that is the besetting weakness of air pollution studies: poor control.

In all the studies of the subject  that have passed across my screen over the years, I doubt that there was a single one that controlled for income. And that is a critical weakness. Perhaps the most regular finding in the whole of the epidemiological literature is that the poor have worse health.  So, without control for income, what you think is a real effect may be entirely an artifact of income.

A typical such study will find that people who live in more polluted areas of a city have worse health than people who live in leafier areas.  But who lives in the leafier areas?  The rich!  Their better health is an income effect, not a pollution effect!

So WHY have we not seen well-controlled studies of urban air-pollution?  I think I know why.  If any such study HAS controlled for income, they most likely found that applying the controls for income knocked an initially weak effect down to non-significance.  And we all know about the bias against reporting "negative" results!

So if we look for well-controlled studies of the effects of air pollution on health or mortality we have to say that there is NO evidence that ordinary urban levels of air pollution have adverse health effects.

You can see the idiocy of worrying about the sort of air pollution we normally experience when we reflect that smokers voluntarily inhale hugely more particulate pollution than others do  -- and yet they have a close to normal life expectancy. Among the famous centenarian Jews of NYC, about a third of them smoke.

So why the attention to air pollution?  The study below is only one of many.  I comment on about two per year and in all cases the effects they describe are weak and turn out on close inspection to be  inconclusive.  So why do such studies? The authors below tell us why they do such studies in the last sentence of their abstract.  It is all an effort to encourage "replacing fossil fuels by clean, renewable energy".  It's just another sermon in support of the Warmist religion, in other words.  Tiresome

Cardiovascular disease burden from ambient air pollution in Europe reassessed using novel hazard ratio functions

Jos Lelieveld et al.

Published: 12 March 2019

Abstract

Aims
Ambient air pollution is a major health risk, leading to respiratory and cardiovascular mortality. A recent Global Exposure Mortality Model, based on an unmatched number of cohort studies in many countries, provides new hazard ratio functions, calling for re-evaluation of the disease burden. Accordingly, we estimated excess cardiovascular mortality attributed to air pollution in Europe.

Methods and results
The new hazard ratio functions have been combined with ambient air pollution exposure data to estimate the impacts in Europe and the 28 countries of the European Union (EU-28). The annual excess mortality rate from ambient air pollution in Europe is 790 000 [95% confidence interval (95% CI) 645 000–934 000], and 659 000 (95% CI 537 000–775 000) in the EU-28. Between 40% and 80% are due to cardiovascular events, which dominate health outcomes. The upper limit includes events attributed to other non-communicable diseases, which are currently not specified. These estimates exceed recent analyses, such as the Global Burden of Disease for 2015, by more than a factor of two. We estimate that air pollution reduces the mean life expectancy in Europe by about 2.2 years with an annual, attributable per capita mortality rate in Europe of 133/100 000 per year.

Conclusion
We provide new data based on novel hazard ratio functions suggesting that the health impacts attributable to ambient air pollution in Europe are substantially higher than previously assumed, though subject to considerable uncertainty. Our results imply that replacing fossil fuels by clean, renewable energy sources could substantially reduce the loss of life expectancy from air pollution.

European Heart Journal





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