April 5, 2020

Among psychologists and those who keep up with those sorts of things, the act of shifting one’s viewpoint from a cup half empty to a cup half-full is called ‘Cognitive reframing.”  This fancier term refers to the psychological technique of identifying and then disputing irrational or maladaptive thoughts; it’s a way of viewing and experiencing events, ideas and concepts to find more positive interpretations.  Basically, it’s learning to reinterpret things and look at the bright side.

An American psychiatrist named Aaron Temkin Beck, who is given credit for developing both cognitive therapy and cognitive behavioral therapy, gave us the actual term “reframing.”  Though it’s hard to imagine the idea really needed inventing. The world has always had people who were born perversely cheerful; people who naturally, or oddly, just see everything in a positive light.

For those of us for whom cheerfulness does not come naturally, this Covid-19 epidemic provides a great chance for us to practice reframing.  We are all aware of the standard view of what’s happened:  The Pandemic is racing through the world, killing thousands and thousands of people, throwing the global economy into the worst recession in history and destroying civilization as we know it.  That’s not even being catastrophic or opening up the Pandora’s Box of negative thinking.

Here’s another way to look at this situation.  We are engaged in a global experiment to test how reducing air pollution will save lives and lead to a cleaner future. 

Two recently published studies can be used to inform this opinion; they have been on my mind these last weeks as we stay at home in Covid-Lockdown mode.  Both studies look at the association between changing levels of air pollution and mortality.  This is totally relevant because the social distancing thing we are doing has had a striking side effect: air pollution levels are falling dramatically as people the world over are stuck with similar lock down measures hoping to slow the virus.[1]

Rather than repeating the mantra, “If we don’t flatten the curve, we are all going to die.”

Try this, “we have all volunteered in a global experiment testing whether lowering air pollution will save lives and reduce disease.”  If you need doctor talk, think a “reduction in air pollution will be associated with improved health, decreased morbidity and a reduction in mortality.” 

The strongest evidence in support of these happy thoughts is the research related to heart disease.  Two major studies were published early this spring with another hand full over the past few years.

The first of the two recent papers was published in Environmental Health February 17, 2020 and written by Bingyu Wang and others at Northeastern University in Boston.  Wang used data from fifty-three million U.S. Medicare recipients (thus aged ≥65) with approximately 4 billion person-months of follow-up..  They combined each individual’s address and zip code to obtain data from the Environmental Protection Agency (EPA).  Using meteorological and geo-temporal models they calculated individual exposure to PM2.5 over an eight-year period (2000-2008).  They compared this calculated PM2.5 exposure against disease specific and all-cause mortality using Cox proportional models.   

They found that PM2.5 was significantly associated with mortality from CVD, respiratory disease, and cancer. A 10 μg /m3 increase in average PM2.5 in the 12-months prior to death was associated with a 5% increase in all-cause mortality, as well as an 8.8% increase in all cardiovascular disease (CVD),  a 5.6% increase in all respiratory, and 2.5% increase in all cancer deaths, respectively, in age, gender, race, ZIP code, and socio-economic status (SES) -adjusted models. PM2.5 exposures, however, were not associated with lung cancer mortality.  The results were the same across gender, race, age, economic status.  There was no evidence of threshold of exposure beneath which PM2.5 was not associated with harm.  [2]

The other study to justify our optimism was by Raymond Pranata et al, which was published on March 13, 2020 in the Journal of Evidence Based Medicine.  It was a comprehensive review and meta-analysis of past studies on air pollution and CVD mortality.  Data from 84 cohorts, comprising a total of 28,215,394 subjects, were combined.  Increases in fine particulate air pollutants were associated with increases in all measures of CVD, acute coronary events, stroke, and high blood pressure.  Mortality rates from CVD increased by 10% for the PM2.5 increases and 17% when the larger PM10 particles were tracked.  Increases in NO, were associated with a 17% increase in CVD mortality and a 23% increase in all-cause mortality. [3]

 While these two recent studies should be enough to break your gloomy mood, there are others we should add to the list.  Hayes et al reported in papers published in July, 2019 and in February 2020 (n=565,477) that for each 10  μg/m3 increase in PM2.5 there was a 16% increase in mortality from ischemic heart disease [hazard ratio (HR) 1.16; 95% CI 1.09-1.22] and a 14% increase in mortality from stroke (HR 1.14; CI 1.02-1.27). [4] [5]

I was first introduced to what a large impact air pollution has on our health by our friend Walter Crinnion ND.  At the time, in 2015, the World Health Organization estimated that air pollution accounted for 1.3 million deaths worldwide every year. Dr. Crinnion, wrote a review article on air pollution and concluded: “It is quite possible that one of the most effective preventive medicine modalities would be the installation of a high-quality air purifier in the home.” [6]  

I thought he had exaggerated the benefits, but I’ve had to cast aside those doubts. We’ve reviewed multiple studies on air pollution since then that suggest an association with a wide range of health conditions.  The focus has been on the ultra-small particulates known as PM2, the teensiest inhalable particles, with diameters that are generally 2.5 micrometers or smaller.  In the monthly Abstracts and Commentary section,  the Natural Medicine Journal (NMJ) has reviewed studies that report  associations between Pm2.5 with obesity[7], diabetes [8], anxiety[9],  suicide [10], psychosis [11], low birth weights[12], decreased cognitive performance[13],  all-cause mortality [14], lung infections [15], and atherosclerosis [16].

The strongest associations have been consistently with cardiovascular disease though. Acute exposure to diesel exhaust causes vascular dysfunction, thrombosis, and myocardial ischemia in healthy individuals and in patients with coronary heart disease.[17] Long term exposure to particulate air pollution is associated with development and progression of atherosclerosis in both animals and humans. [18]   Miller et al provided evidence for the mechanism underlying this in 2017.  Inhaled particles deposit deep in the lungs and trigger oxidative stress and inflammation. [19] The nanoparticles then penetrate the alveolar epithelium and translocate into the circulation and these particles accumulate at sites of vascular inflammation. How readily the particles translocate depends on their size; the smaller the particle, the easier they translocate and accumulate.  [20] 

The range of prognostic numbers we find in these papers by Wang, Pranata, Hayes and others might be used when looking at our current lockdown.  The predictions vary from a 5% increase in all-cause mortality (Wang), a 10% increase in CVD mortality (Pranata) to a 16% increase in mortality from ischemic heart disease (Hayes) for a upward shift of 10 μg /m3 in average PM2.5.  [There is also Pope et al:  in 2015 they reported that for a similar PM2.5 increase there was a 12% increase in CVD deaths. [21]]

These findings provide a crude gauge with which to make estimates of what we might predict to see in future studies that look back on our current time period in regard to CVD mortality.

In an article posted in early March on the academic website G-Feed, Marshall Burke, a professor at Stanford’s Environmental Earth Systems Science Department, calculated that the decreased air pollution in China this past winter, may have saved twenty times more lives  than were lost due to the Covid-19 infection the that country. [22] Now that is certainly one optimistic view of a disaster.  Burke relied on older Chinese research to make his calculation; neither Pranata nor Wang had been published when he was doing his calculations. [23]  

Burke utilized the 2016 findings from Su et al who had analyzed data collected during the 2008 Summer Olympics and Paralympic Games. Recall how China went to great efforts to reduce ambient air pollution during the games by restricting traffic and shutting down pollution sources.  [24]  Burke estimated that the current shutdown in response to Covid-19, resulted in “… about a 10ug/m3 reduction in PM across China in Jan-Feb of 2020 relative to the same months in the previous 2 years.”  He et al had reported, “… that a 10 percent decrease in concentrations reduces the monthly standardized all-cause mortality rate by 8 percent.” [25]

Burke writes, “Putting these numbers together …. yields some very large reductions in premature mortality… I calculate that having 2 months of 10ug/m3 reductions in PM2.5 likely has saved the lives of 4,000 kids under 5 and 73,000 adults over 70 in China.” 

On April 3, 2020, the European Union’s Copernicus Atmosphere Monitoring Service announced that when they compared the difference between the monthly average for February 2020 and the mean of monthly averages for February 2017, 2018 and 2019, they measured  a 20-30 % reduction in surface PM2.5 over large parts of China in February 2020 from their satellite observations.  [26]

The U.S. started out with much cleaner air than China so perhaps these relationships will not apply the same way.  Yet recall that Wang et al, reported, “…. no evidence of a lower threshold for response or of lower Risk Ratios (RRs) at low PM2.5 levels.”  This suggests that lowering our own pollution levels may still results in significant improvements.  

About 647,000 people die in the US each year from CVD.[27]  If our staying at home were to lower this figure by 10% (to use Burke’s conservative figure), that would prevent nearly 65,000 deaths from CVD alone, a change that would be hard not to notice.   Pranata’s 16% decrease could save over 103,000 lives a year.

Let’s look forward to the future when we see more accurate measures of the true impact air pollution has and perhaps be able to more accurately calculate the cost of dirty air to communal health. We naturopathic sorts have always put a high value on a clean world.  This is our chance to prove that it is worthwhile to make the needed efforts.  We’re part of a large experiment; we need to be patient until the data can be be collected and analyzed.

Our experiment may be confounded by other concurrent events.  The EPA continues to roll back pollution enforcement rules and other policies put in place to reduce environmental pollution.  Let us hope that they do not negate our efforts.  Job loss and the related shifts that unemployment have on heart health outcomes will also need to be taken into account.  

Am I delusional, as some suggest?  In support of my hopes, let me point to an April 6, 2020 article in the NY Times written by cardiologist Harlan Krumholz.  He describes being surprised by the lack of the normally expected numbers of cardiac patients at his hospital and goes on to write, “cardiologists have shared with me that their cardiology consultations have shrunk, except those related to Covid-19. In an informal Twitter poll by ….. almost half of the respondents reported that they are seeing a 40 percent to 60 percent reduction in admissions for heart attacks; about 20 percent reported more than a 60 percent reduction.”[28]

I’m far from perfect at this whole reframing thing and though I spend some of the day relishing how blue the sky has become, I also spend time experiencing a level of anxiety similar to if I were playing Russian roulette. Looking on the bright side of things takes practice.  This plague certainly will provide plenty of opportunity.   Yet with practice, think of all the things we used to worry about and how easy it is going to be to reframe them in the future.

[1] https://www.bbc.com/news/world-asia-51691967

[2] Wang B, Eum KD, Kazemiparkouhi F, Li C, et al. The impact of long-term PM2.5 exposure on specific causes of death: exposure-response curves and effect modification among 53 million U.S. Medicare beneficiaries. Environ Health. 2020 Feb 17;19(1):20. 

[3] Pranata R, Vania R, Tondas AE, Setianto B, Santoso A. A time-to-event analysis on air pollutants with the risk of cardiovascular disease and mortality: A systematic review and meta-analysis of 84 cohort studies. J Evid Based Med. 2020 Mar 13.   

[4] Hayes RB, Lim C, Zhang Y, et al. PM2.5 air pollution and cause-specific cardiovascular disease mortality. Int J Epidemiol. 2019 Jul 10. pii: dyz114. 

[5] Hayes RB, Lim C, Zhang Y, et al. PM2.5 air pollution and cause-specific cardiovascular disease mortality. Int J Epidemiol. 2020 Feb 1;49(1):25-35. 

[6] Crinnion W, Air Pollution, Disease, and Mortality: Particulate matter as a global health threat.Natural Medicine Journal. 2015 vol. 7:91.  https://www.naturalmedicinejournal.com/journal/2015-09/air-pollution-disease-and-mortality

[7] Alderete TL, Habre R, Toledo-Corral CM, et al. Longitudinal associations between ambient air pollution with insulin sensitivity, β-cell function, and adiposity in Los Angeles Latino children [published online ahead of print January 30, 2017]. Diabetes.

[8] Solimini AG, D’Addario M, Villari P. Ecological correlation between diabetes hospitalizations and fine particulate matter in Italian provinces. BMC Public Health.2015;15(1):708.

[9] Power MC, Kioumourtzoglou MA, Hart JE, Okereke OI, Laden F, Weisskopf MG. The relation between past exposure to fine particulate air pollution and prevalent anxiety: observational cohort study. BMJ. 2015 Mar 24;350:h1111. 

[10] Bakian AV, Huber RS, Coon H, et al. Acute air pollution exposure and risk of suicide completion. Am J Epidemiol. 2015;181(5):295-303.

[11] Newbury J, Arseneault L, Beevers, S, et al. Association of air pollution exposure with psychotic experiences during adolescence [published online ahead of print March 27, 2019]. JAMA Psychiatry.

[12] Smith RB, Fecht D, Gulliver J, et al. Impact of London’s road traffic air and noise pollution on birth weight: retrospective population based cohort study. BMJ. 2017;359:j5299.

[13] Zhang X, Chen X, Zhang X. The impact of exposure to air pollution on cognitive performance. Proc Natl Acad Sci U S A. 2018;115(37):9193-9197.

[14] Di Q, Dai L, Wang Y, et al. Association of short-term exposure to air pollution with mortality in older adults. JAMA. 2017;318(24):2446-2456

[15] Horne BD, Joy EA, Hofmann MG, et al. Short-term elevation of fine particulate matter air pollution and acute lower respiratory infection [published online ahead of print April 13, 2018]. Am J Respir Crit Care Med.

[16] Miller MR, Raftis JB, Langrish JP, et al. Inhaled nanoparticles accumulate at sites of vascular disease. ACS Nano. 2017;11(5):4542-4552.

[17] Lucking AJ, Lundback M, Mills NL, et al. Diesel exhaust inhalation increases thrombus formation in man. Eur Heart J. 2008;29(24):3043-3051.

[18] Brook RD. Cardiovascular effects of air pollution. Clin Sci (Lond). 2008;115(6):175-187

[19] Miller MR, Shaw CA, Langrish JP. From particles to patients: oxidative stress and cardiovascular effects of air pollution. Future Cardiol. 2012;8(4):577-602.

[20] Hussain M, Wu D, Saber AT, et al. Intratracheally instilled titanium dioxide nanoparticles translocate to heart and liver and activate complement cascade in the heart of C57BL/6 mice. Nanotoxicology. 2015;9(8):1013-1022.

[21] Pope CA 3rd, Turner MC, Burnett RT, et al. Relationships between fine particulate air pollution, cardiometabolic disorders, and cardiovascular mortality. Circ Res. 2015 Jan 2;116(1):108-15. 

[22] https://www.independent.co.uk/environment/satellite-images-emissions-climate-crisis-coronavirus-europe-map-a9426436.html

[23] http://www.g-feed.com/2020/03/covid-19-reduces-economic-activity.html

[24] Su C, Hampel R, Franck U, et al. Assessing responses of cardiovascular mortality to particulate matter air pollution for pre-, during- and post-2008 Olympics periods. Environ Res. 2015 Oct;142:112-22. 


[25] He G, Fan M, Zhou M et al. The effect of air pollution on mortality in China: Evidence from the 2008 Beijing Olympic Games. J Env Econ & Man.V 79, Sep 2016, pgs. 18-39.


[26] https://atmosphere.copernicus.eu/amid-coronavirus-outbreak-copernicus-monitors-reduction-particulate-matter-pm25-over-china. April 3, 2020

[27] https://www.cdc.gov/heartdisease/facts.htm

[28] Harlan Krumholz.  Where Have All the Heart Attacks Gone?  NY Times. Apr 6, 2020.