S. Stanley Young and Warren B. Kindzierski. Evaluation of a meta-analysis of air quality and heart attacks, a case study. Critical Reviews in Toxicology https://doi.org/10.1080/10408444.2019.1576587
It is generally acknowledged that claims from observational studies often fail to replicate. An exploratory study was undertaken to assess the reliability of base studies used in meta-analysis of short-term air quality-myocardial infarction risk and to judge the reliability of statistical evidence from meta-analysis that uses data from observational studies. A highly cited meta-analysis paper examining whether short-term air quality exposure triggers myocardial infarction was evaluated as a case study. The paper considered six air quality components – carbon monoxide, nitrogen dioxide, sulphur dioxide, particulate matter 10 lm and 2.5 lm in diameter (PM10 and PM2.5), and ozone. The number of possible questions and statistical models at issue in each of 34 base papers used were estimated and p-value plots for each of the air components were constructed to evaluate the effect heterogeneity of p-values used from the base papers. Analysis search spaces (number of statistical tests possible) in the base papers were large, median 1⁄4 12,288 (interquartile range 1⁄4 2496 ” 58,368), in comparison to actual statistical test results presented. Statistical test results taken from the base papers may not provide unbiased measures of effect for meta-analysis. Shapes of p-value plots for the six air components were consistent with the possibility of analysis manipulation to obtain small p-values in several base papers. Results suggest the appearance of heterogeneous, researcher-generated p-values used in the meta-analysis rather than unbiased evidence of real effects for air quality. We conclude that this meta-analysis does not provide reliable evidence for an association of air quality components with myocardial risk.
James E. Enstrom. Scientific Distortions in Fine Particulate Matter Epidemiology. Journal of American Physicians and Surgeons Volume 23 Number 1 Spring 2018
The theoretical prevention of premature deaths from the inhalation of fine particulate matter is being used by the U.S. Environmental Protection Agency (EPA) to justify the National Ambient Air Quality Standard (NAAQS) and multibillion dollar regulations across the U.S., including the EPA Clean Power Plan and the California Air Resources Board (CARB) Truck and Bus Regulation. The epidemiology is severely flawed. Fine particulates probably make no significant contribution to premature mortality in the U.S. The publication of null findings has been blocked or marginalized and studies claiming excess mortality need to be reassessed. click here
The Environmental Protection Agency issued a guidance to clear up uncertainties in obtaining air quality permits required to build or modify facilities, like power plants and refineries. click here
“This letter is not a letter to the editor, hoping for publication, so that the authors might comment on or criticize some article in the NEJM. We write to complain that there is a continuing scandal of scientific integrity at the NEJM—junk science in air pollution epidemiology is being sponsored by what most would consider the iconic medical journal of America.” click here
“Clearly we don’t know everything about asthma, but there is little evidence to suggest that air pollution from traffic makes much difference.” click here
Peng Yin, Guojun He, Maoyong Fan, Kowk Yan Chiu, Maorong Fan, Chang Liu, An Xue, Tong Liu, Yuhang Pan, Quan Mu, Maigeng Zhou. Particulate air pollution and mortality in 38 of China’s largest cities: time series analysis. BMJ 2017;356:j667 doi: https://doi.org/10.1136/bmj.j667
The findings of this particular study (click here) and been seriously questioned (click here). If not considered, cigarette smoking is a huge confounding factor in any study involving the respiratory system. Confidence limits on the analysis must be considered when evaluating data.