Genes, Evolution, and Air Pollution

by Marion Fintel | Mar 4, 2020

Genes, Evolution, and Air Pollution

I believe that the health of each and every one of us is harmed by air pollution. I base this belief on studies that show there is no safe level of pollutants and that adverse health effects are occurring at levels much lower than previously thought. It is hard, given the many factors that play a role in triggering a particular disease, to tease apart the role played by exposure to air pollutants. However, carefully designed investigations that control for variables such as smoking and that involve large numbers of participants have been able to do just that.

The World Health Organization estimates that in 2016 almost 70,000 deaths in the US could be attributed to ambient air pollution. And yet, not everyone exposed to air pollution will get sick and have a premature death. Exposure to air pollutants may make our respiratory tract constrict and our eyes burn without ever causing us to come down with a specific disease. Why is it that one person exposed to air pollution will have a heart attack or die from pneumonia, while another person with the same exposure won’t? The elderly, children, and those with pre-existing disease have been shown to be more at risk than healthy young adults. Not surprisingly, our genes are also very important.

A literature review by Benjamin Trumble and Caleb Finch in 2019 described how particular genes selected for in the course of human evolution may be key in determining an individual’s susceptibility to the ill effects of pollutants. One such gene variation (allele) is the ApoE4 gene. ApoE genes code for ApoE proteins, which play a role in cholesterol and triglyceride (fat) transport and immune function. The three ApoE alleles are ApoE2, ApoE3, and ApoE4, the most common of which is the ApoE3 allele.

The ApoE4 allele has been associated with an increased risk of Alzheimer’s Disease and increased dementia risk from air pollutants. In the course of human evolutionary history, this allele conveyed a survival advantage, but in our present industrialized world, it is maladaptive.

I don’t know if I have the ApoE4 gene or not. I don’t know if I have any of the other gene variants that Trumble and Finch discuss that increase the health risk from air pollution. I do know that children living in highly polluted, often low-income and minority neighborhoods, are suffering from life-threatening asthma because of the dirty air they breathe.

I know that older individuals are experiencing heart attacks, worsening of emphysema, and the onset of dementia due to the dirty air they breathe. And I know that individuals are dying from lung cancer and bladder cancer because of the dirty air they breathe. I do belong to one of the groups more at risk from pollutants; I am in the 65 or older age group.

I don’t want my health harmed, and I don’t want anyone else’s health harmed, because a company doesn’t want to spend the money to protect our environment. For this reason, I am a proud supporter of the work that Gasp is doing to clean up our air and hope you are as well.

Reference: Trumble BC, Finch CE. (2019). The exposome in human evolution from dust to diesel. The Quarterly Review of Biology. 94(4) 333-394.

Dr. Marion Fintel

Volunteer

Marion Fintel retired from Talladega College as an associate professor of biology in July of 2019. During her career, she taught anatomy and physiology, as well as other biology courses, to college students for close to thirty years. Dr. Fintel earned her doctorate in physiology from LSU Health Sciences Center in New Orleans in 1982. She then received further research training as a postdoctoral scholar in the UCLA Department of Physiology. In 2013, Dr. Fintel earned a masters of science degree in public health (MSPH) in the field of epidemiology from UAB.

Scientific Advisory Board Pushes Back on Trump’s EPA Rollbacks

by Marion Fintel | Jan 7, 2020

Scientific Advisory Board Pushes Back on Trump’s EPA Rollbacks

I lived in Los Angeles from 1982 through 1986. During that time, I was often homesick for the region I grew up in and was educated in, the Southeast. When I had the opportunity to move back to the area by taking a job at UAB, I jumped at the chance. One of the many things I missed while living in LA was blue sky. I only saw truly blue sky when I traveled out of the city. The sky in LA seemed forever hazy with only a slight blue tinge.

Fortunately, much has changed in the 33 years since I left Los Angeles. Periodically I have returned there and marveled at the current blueness of the LA sky. More people than ever now live in LA, there are more vehicles on the road, but the air is cleaner. California took steps to strictly regulate vehicle emissions and the state’s efforts paid off. LA still has a serious problem with air pollution, as does our own city of Birmingham, but state and local regulations and policies have made a difference. I can literally see it. Unfortunately, this progress has been put in jeopardy by proposals put forward by the Trump Administration.

The Trump Administration has been attempting to roll back environmental protections ever since it came into office. With regard to air quality, vehicle fuel emissions standards were put in place by the Obama Administration that would require an average fuel efficiency of 54.5 miles per gallon by 2025, if the emissions standards were solely met by improving fuel efficiency. In August of 2018, the Trump Administration made a proposal to freeze the standard at 37 miles per gallon.

The Trump Administration has also proposed revoking the legal waiver given to California and other states, which permits them to set their own stringent standards on vehicle emissions. According to a report in the New York Times, the Scientific Advisory Board to the Environmental Protection Agency has posted draft letters online that call into question the scientific analysis that supports Trump’s vehicle emissions proposals, as well as proposals related to water quality and public health research. The Board’s defense of scientific integrity is all the more noteworthy because of the many Trump appointees that are now a part of it.

From: Clay K and Muller N. Recent increases in air pollution: evidence and implications for mortality. National Bureau of Economic Research. October 2019. Reproduced with permission from Clay and Muller.

Karen Clay and Nicholas Muller reported in October of 2019 that particulate matter pollution less than 2.5 microns in diameter (PM 2.5) has increased in the US by 5.5% in the years between 2016 and 2018, after a seven year period of decline. Clay and Muller discussed possible causes of this increase, which include increased economic activity, wildfires, and decreased environmental enforcement actions. PM 2.5 is a cause of heart attacks.

The air we breathe needs to be cleaned up, not allowed to get dirtier. Lives depend on it. A colleague’s wife when I lived in LA in the 1980s was diagnosed with lung cancer. As another colleague explained, she had never smoked, but this is something that can happen when pollution is high. Despite the progress made in Los Angeles over the past 33 years, there is much more clean-up that is needed. According to the LA County Department of Public Health, the rate of asthma among African American children living in the LA area was an unacceptable 18% in 2015.

Recent research has linked air pollution with dementia, as Anna Vantsevich discusses in her blog post. Strict environmental standards and strict enforcement of environmental regulations not only make the LA sky blue, they protect our health and that of our children. The federal government needs to assist states like California that are willing and able to clean up their air, not stand in the way. Let us hope that the Trump Administration will listen to the scientific advisors that it selected and reconsider these proposals that will dirty up our air.

References

https://www.nytimes.com/2019/12/31/climate/epa-science-panel-trump.html

https://www.nytimes.com/2018/08/02/climate/trump-auto-emissions-california.html

https://yosemite.epa.gov/sab/sabproduct.nsf/ea5d9a9b55cc319285256cbd005a472e/3bd8a1aea4943223852584e1005463de/$FILE/SAFE%20SAB%20Draft%20Review_10_16_19_.pdf

https://nepis.epa.gov/Exe/ZyPDF.cgi/P100EZ7C.PDF?Dockey=P100EZ7C.PDF

https://www.nber.org/papers/w26381

http://publichealth.lacounty.gov/mch/AsthmaCoalition/statsreports.htm

Dr. Marion Fintel

Volunteer

Assessing Causality of Particulate Matter Pollution on Health

by Marion Fintel | Dec 17, 2019

Assessing Causality of Particulate Matter Pollution on Health

The Clean Air Scientific Advisory Committee (CASAC) of the Environmental Protection Agency (EPA) makes recommendations to the EPA administrator regarding National Ambient Air Quality Standards for criteria air pollutants, including particulate matter. This process requires CASAC to analyze research and make determinations regarding causality. A particular study may show a clear association between two variables, but an association does not necessarily mean causation. Recent research has shown that particulate matter less than 2.5 microns (PM 2.5) is causing health problems at concentrations lower than expected and below the current standard. This indicates that the standard needs to be lowered in order to protect our health. At the same time, the chair of CASAC, Dr. Louis Anthony (Tony) Cox Jr., has been trying to drastically change the process by which causality is evaluated by the EPA. There is concern that this new untried approach, known as manipulative causation, would allow important studies that demonstrate the need for stricter standards to be discounted and ignored.

Emissions polluting the air from Bluestone Coke (formerly known as ERP Coke & Walter Coke)

The analytic framework that the EPA has been using, the one this new approach would replace, incorporates and expands on the well-established and widely-accepted guidelines put forth by Bradford Hill in 1965 for assessing causality. The Bradford Hill guidelines are: temporality, analogy, consistency, plausibility, coherence, specificity, biological gradient, experiment, and strength. Using these guidelines, the causal nature of the association of PM 2.5 and health effects is clear. The guideline of temporality is satisfied because exposure to PM 2.5 occurs before the health problems happen. By analogy, the harmful effects of PM 2.5 are in line with the well-documented harmful effects of smoking. The observational studies consistently show similar effects of particulate matter on health among different populations. The adverse health effects of PM 2.5 are worse at higher levels indicating a biological gradient, otherwise known as a dose-response relationship. For obvious reasons, researchers cannot intervene and expose study participants to high levels of PM 2.5 for a long period of time. For this reason, experimental studies with animals and short-term exposure experiments with humans are very important. These experiments have demonstrated adverse effects that reinforce the conclusions from observational studies. The results from varied types of studies are coherent with one another. The mechanism by which air pollutants causes harm involves pulmonary and systemic oxidative stress leading to chronic inflammation and DNA damage. Delineation of this mechanism has meant that the harmful effects of PM 2.5 on human health are biologically plausible.

Appropriate usage of the Bradford Hill guidelines does not require that all nine guidelines be satisfied in order to attribute causality. Current scientific evidence satisfies most of the Bradford Hill guidelines for causality with two exceptions. Because PM 2.5 causes oxidative stress and chronic inflammation, many organs are affected and the effects are not specific. The other exception is the guideline of strength. Exposure to PM 2.5 increases the risk of various health effects by relatively small percentages compared to smoking, but because of the large percentage of people who are exposed to air pollution, the toll air pollution takes on human health is substantial. PM 2.5 has definitively been shown to increase the risk of cardiopulmonary diseases (e.g. heart attacks, heart failure, lung cancer), cardiopulmonary mortality, and all-cause mortality.

The World Health Organization estimates that 4.2 million premature deaths occurred in 2016 because of outdoor air pollution. It is imperative that the EPA fully and carefully analyzes all of the relevant research and acts to protect our health by reducing particulate matter pollution.

References:

Bowe B, Xie Y, Yan Y, Al-Aly Z. (2019). Burden of cause-specific mortality associated with PM 2.5 air pollution in the United States. JAMA Network Open.

Goldman GT, Dominici F. (2019). Don’t abandon evidence and process on air pollution policy. Science. 3631398-1400.

Hill AB. (1965). The environment and disease: association or causation? Journal of the Royal Society of Medicine. 108: 32-37.