Junk medical epidemiology on air pollution

These researchers used the same lousy methodology, but at least they were willing to admit they didn’t find anything. What they do claim is not statistically valid.

The results show no acute air pollution effect on heart attacks. And they squeezed out some statistically invalid results on arrhythmia and pulmonary embolism, but so many times their results include a confidence interval that includes 1.0–Church Lady disapproves.

Can I help you out here, the research that is used to claim hundreds of thousands of deaths from air pollution is JUNK.

The epidemiology that they use is the projection of data dredged events well within the margin of error or the daily variability for deaths. It is an observational study, so the association has to be robust–it never is.

For example we have repeatedly pointed out that in epidemiology small associations don’t prove causation, but the EPA and WHO and their paid researcher and policy allies point to small associations, project to large populations and voila, they have a large number of deaths or disease events to associate with air pollution./

Then they do projections, which is how they got to millions dead from indoor pollution.

And they ignore their basic methodology problems–

1. Acute events from air pollution?
2. Failure to establish a plausible mechanism for events.
3. Events counted, even deaths, but no actuarial analysis for life expectancy of the dead and no effort to evaluate for confusing or confounding factors.
4. Arbitrary choice of lag times, providing an opportunity for data dredge.
5. A very loose inclusion of all cardiorespiratory deaths in the death studies, and in this particular study, for the cardiovascular events.
6. No knowledge of actual exposure of the individuals to indoor or outdoor pollution, just area wide monitor information. People live indoors.

With those things in mind, here is the journal article forwarded by Marc Morano.

One consoling fact is that these researchers actually reported a null effect for air pollutants, which means no more research money for them.

Thanks Marc Morano–udaman.

New paper finds no association between air pollution and heart attacks


Morano comments:

A new paper published in The British Medical Journal Heart finds “no clear evidence for pollution effects on heart attacks and stroke, though it did for pulmonary embolism.” The study was one of the largest of its kind and analyzed over 2 million cardiovascular events in England and Wales.The study analyzed actual air pollutants such as carbon monoxide (CO), nitrogen dioxide (NO2), particulate matter, sulfur dioxide (SO2), and ozone (O3). Note CO2 was not studied for associations since, despite the claims of President Obama and EPA administrator McCarthy, CO2 is not “carbon pollution” and does not have any association with heart attacks, asthma, or any other public health effects.

Journal link to the British Medical Journal Heart


Cardiac risk factors and prevention

Original article

Short-term effects of air pollution on a range of cardiovascular events in England and Wales: case-crossover analysis of the MINAP database, hospital admissions and mortality
Ai Milojevic1,
Paul Wilkinson1,
Ben Armstrong1,
Krishnan Bhaskaran2,
Liam Smeeth2,
Shakoor Hajat1

+Author Affiliations

1Department of Social and Environmental Health Research, London School of Hygiene and Tropical Medicine, London, UK

2Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK

Correspondence toDr Ai Milojevic, Department of Social and Environmental Health Research, London School of Hygiene & Tropical Medicine, 15-17 Tavistock Place, London, WC1H 9SH, UK;ai.milojevic@lshtm.ac.uk

Published Online First 4 June 2014


Objective To inform potential pathophysiological mechanisms of air pollution effects on cardiovascular disease (CVD), we investigated short-term associations between ambient air pollution and a range of cardiovascular events from three national databases in England and Wales.

(Dunn note: again, how can they do short-term, short lag time studies? They have no mechanism for acute deaths or events from air pollutants.)

Methods Using a time-stratified case-crossover design, over 400 000 myocardial infarction (MI) events from the Myocardial Ischaemia National Audit Project (MINAP) database, over 2 million CVD emergency hospital admissions and over 600 000 CVD deaths were linked with daily mean concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), particulate matter less than 10 μm in aerodynamic diameter (PM10), particulate matter less than 2.5 μm in aerodynamic diameter (PM2.5) and sulfur dioxide (SO2), and daily maximum of 8-hourly running mean of O3 measured at the nearest air pollution monitoring site to the place of residence. Pollutant effects were modelled using lags up to 4 days and adjusted for ambient temperature and day of week.

Results For mortality, no CVD outcome analysed was clearly associated with any pollutant, except for PM2.5 with arrhythmias, atrial fibrillation and pulmonary embolism. With hospital admissions, only NO2 was associated with a raised risk: CVD 1.7% (95% CI 0.9 to 2.6), non-MI CVD 2.0% (1.1 to 2.9), arrhythmias 2.9% (0.6 to 5.2), atrial fibrillation 2.8% (0.3 to 5.4) and heart failure 4.4% (2.0 to 6.8) for a 10th–90th centile increase. With MINAP, only NO2 was associated with an increased risk of MI, which was specific to non-ST-elevation myocardial infarction (non-STEMIs): 3.6% (95% CI 0.4 to 6.9).

(Dunn note: the Confidence intervals on these associations means they are meaningless. When the CI includes 1.0 it means–there is no possibility of proof of causation. When the CI is large, as in more than 2, it means that the sample size is too small for good confidence that it meets the rule on statistical significance and P values of 0.05. As for including congestive heart failure in the study, they should be ashamed of themselves. There is no known mechanism for acute congestive heart failure that fits their study.)

Conclusions This study found no clear evidence for pollution effects on STEMIs and stroke, which ultimately represent thrombogenic processes, though it did for pulmonary embolism. The strongest associations with air pollution were observed with selected non-MI outcomes.

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3 responses to “Junk medical epidemiology on air pollution

  1. What I find interesting is that they found some association with measurements of PM 2.5 but not PM 10. Measured PM 10 includes PM 2.5 so what is really going on.

  2. The short answer is Nothing is going on.

    The long answer is that they look at an awful lot of things. I count a hundred or so. A few things were “statistically significant” without correcting the analysis for the number of questions asked. If you test 100 things you expect ~5% to be statistically significant.

    PM10 is not perfectly correlated with PM2.5. The PM10 result is likely chance.

    Now re-read the short answer.

  3. The association was with PM 2.5 and not PM 10 which was my point. PM 10 includes PM 2.5 thus it makes no sense.

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