Mitigating the Effects of Pollutants on Disease

David B. Peden, MD, MS

Ambient and indoor pollutants have a significant impact on health, causing inflammation, asthma exacerbation, and increasing the risk of cardiovascular disease and infection, but their adverse effects can be mitigated by the use of medications and policy interventions.

The 2 main culprits, ozone and particulate matter (PM), each have a respective list of actions and acute impacts. Ozone causes nociceptive airway restriction, acute airway inflammation, increased permeability, and increased airway reactivity, while PM can cause some airway reactivity, inflammation, decreased lung function, and effects on the cardiovascular system.

In a presentation at the 2018 American Academy of Allergy, Asthma, and Immunology (AAAAI)/World Allergy Organization (WAO) Joint Congress in Orlando, Florida, David B. Peden, MD, MS, stressed the need to extend the current phase 1 proof of concept studies to phase 3 and for physicians to get involved with public policy to improve the current situation.

“Show up in to these meetings a white coat, tell them you're a doctor, and help generate change,” Peden, the Andrews Distinguished Professor of Pediatrics, the senior associate dean for translational research at the University of North Carolina, and the director of UNC’s Center for Environmental Medicine, Asthma, and Lung Biology, said. “Tell them what we know—that air pollution is damaging and, in some cases, is killing people.”

During his presentation, Peden pointed out that policy interventions have been shown to work previously. During the 1996 summer Olympic games in Atlanta, Georgia, policy interventions restricted pollutants more strictly than normal. According to results of a study conducted by Michael A. Friedman, MD, et. al., the levels of major pollutants as measured by a percentage of National Ambient Air Quality Standard (NAAQS) were shown to decrease noticeably during the Olympic period.

The study showed that hospitalizations for asthma were reduced by 19.1%, and the number of emergency care visits and hospitalizations decreased 41.6% per day (4.23 per day at baseline; 2.47 per day during the Olympic period). Additionally, during the Olympic period, pediatric emergency department visits decreased 11.1%.

“Another study from 2105 showed that lung function growth was associated with higher levels of cleaner air,” Peden said. “Cleaner air means healthier lungs.”

The study, by W. James Gaurderman, PhD, et. al. showed that in southern California, the proportion of 2120 children with clinically low forced expiratory volume in 1 second (FEV₁) had declined significantly by age 15, from 7.95 to 6.3% to 3.6% (P = .001) as air quality improved from 3 periods, 1994—1998, 1997–2001, and 2007-2011.

Cleaner air is the main objective, Peden said, but in the meantime, there is a need for interventions to help treat those impacted by pollutants. “Though, there are no chemoprevention therapies for the effects of air pollutants approved by the US Food and Drug Administration,” he said.

Peden said that inhaled corticosteroids have been shown to reduce baseline eosinophilic inflammation, as well as CD14 expression on airway macrophages and monocytes, and the influx of PM in phase 1 studies. Cytokine-directed agents, such as interleukin-1 and interleukin-8 receptor antagonists have also been shown to reduce endotoxin-induced airway inflammation in early stage examinations.

Phase 1-2 proof of concept studies have been conducted for inhaled corticosteroids, anakinra, gamma tocopherol, and hypertonic saline, and were successful, but they need to be advanced in order to explore their potential benefits.

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