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CME / ABIM MOC / CE

Does Air Pollution Affect COVID-19 Outcomes?

  • Authors: News Author: Pam Harrison; CME Author: Laurie Barclay, MD
  • CME / ABIM MOC / CE Released: 7/8/2022
  • Valid for credit through: 7/8/2023
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  • Credits Available

    Physicians - maximum of 0.25 AMA PRA Category 1 Credit(s)™

    ABIM Diplomates - maximum of 0.25 ABIM MOC points

    Nurses - 0.25 ANCC Contact Hour(s) (0 contact hours are in the area of pharmacology)

    Pharmacists - 0.25 Knowledge-based ACPE (0.025 CEUs)

    Physician Assistant - 0.25 AAPA hour(s) of Category I credit

    IPCE - 0.25 Interprofessional Continuing Education (IPCE) credit

    You Are Eligible For

    • Letter of Completion
    • ABIM MOC points

Target Audience and Goal Statement

This activity is intended for infectious disease clinicians, internists, public health and prevention officials, physician assistants, nurses, pulmonologists, pharmacists, and other members of the healthcare team who take of patients with COVID-19 who may be at risk for worse outcomes because of exposure to air pollution.

The goal of this activity is that learners will be better able to describe the association of long-term exposure to ambient air pollution with COVID-19 severity, reflected in risk for COVID-19-related hospital admission, intensive care unit (ICU) admission and death, according to a prospective cohort study of all people with confirmed SARS-CoV-2 infection, aged ≥ 20 years and not residing in a long-term care facility in Ontario, Canada during 2020.

Upon completion of this activity, participants will:

  • Describe the association of long-term exposure to ambient air pollution with COVID-19 severity, according to a prospective cohort study in Ontario, Canada, during 2020
  • Identify clinical and public health implications of the association of long-term exposure to ambient air pollution with COVID-19 severity, according to a prospective cohort study in Ontario, Canada, during 2020
  • Outline implications for the healthcare team


Disclosures

Medscape, LLC requires every individual in a position to control educational content to disclose all financial relationships with ineligible companies that have occurred within the past 24 months. Ineligible companies are organizations whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or on patients.

All relevant financial relationships for anyone with the ability to control the content of this educational activity are listed below and have been mitigated according to Medscape policies. Others involved in the planning of this activity have no relevant financial relationships.


News Author

  • Pam Harrison

    Freelance writer, Medscape

    Disclosures

    Pam Harrison has no relevant financial relationships.

CME Author

  • Laurie Barclay, MD

    Freelance writer and reviewer
    Medscape, LLC

    Disclosures

    Laurie Barclay, MD, has the following relevant financial relationships:
    Formerly owned stocks in: AbbVie Inc.

Editor/Nurse Planner

  • Leigh A. Schmidt, MSN, RN, CMSRN, CNE, CHCP

    Associate Director, Accreditation and Compliance
    Medscape, LLC

    Disclosures

    Leigh A. Schmidt, MSN, RN, CMSRN, CNE, CHCP, has no relevant financial relationships.

Compliance Reviewer

  • Yaisanet Oyola, MD

    Associate Director, Accreditation and Compliance
    Medscape, LLC

    Disclosures

    Yaisanet Oyola, MD, has no relevant financial relationships.

Peer Reviewer

This activity has been peer reviewed and the reviewer has no relevant financial relationships.


Accreditation Statements



In support of improving patient care, Medscape, LLC is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.

This activity was planned by and for the healthcare team, and learners will receive 0.25 Interprofessional Continuing Education (IPCE) credit for learning and change.

    For Physicians

  • Medscape, LLC designates this enduring material for a maximum of 0.25 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

    Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to 0.25 MOC points in the American Board of Internal Medicine's (ABIM) Maintenance of Certification (MOC) program. Participants will earn MOC points equivalent to the amount of CME credits claimed for the activity. It is the CME activity provider's responsibility to submit participant completion information to ACCME for the purpose of granting ABIM MOC credit.

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    For Nurses

  • Awarded 0.25 contact hour(s) of continuing nursing education for RNs and APNs; none of these credits is in the area of pharmacology.

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    For Pharmacists

  • Medscape, LLC designates this continuing education activity for 0.25 contact hour(s) (0.025 CEUs) (Universal Activity Number JA0007105-0000-22-198-H01-P).

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  • For Physician Assistants

    Medscape, LLC has been authorized by the American Academy of PAs (AAPA) to award AAPA Category 1 CME credit for activities planned in accordance with AAPA CME Criteria. This activity is designated for 0.25 AAPA Category 1 CME credits. Approval is valid until 7/8/2023. PAs should only claim credit commensurate with the extent of their participation.

For questions regarding the content of this activity, contact the accredited provider for this CME/CE activity noted above. For technical assistance, contact [email protected]


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This activity is designed to be completed within the time designated on the title page; physicians should claim only those credits that reflect the time actually spent in the activity. To successfully earn credit, participants must complete the activity online during the valid credit period that is noted on the title page. To receive AMA PRA Category 1 Credit™, you must receive a minimum score of 75% on the post-test.

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You may now view or print the certificate from your CME/CE Tracker. You may print the certificate but you cannot alter it. Credits will be tallied in your CME/CE Tracker and archived for 6 years; at any point within this time period you can print out the tally as well as the certificates from the CME/CE Tracker.

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CME / ABIM MOC / CE

Does Air Pollution Affect COVID-19 Outcomes?

Authors: News Author: Pam Harrison; CME Author: Laurie Barclay, MDFaculty and Disclosures

CME / ABIM MOC / CE Released: 7/8/2022

Valid for credit through: 7/8/2023

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Note: The information on the coronavirus outbreak is continually evolving. The content within this activity serves as a historical reference to the information that was available at the time of this publication. We continue to add to the collection of activities on this subject as new information becomes available. It is the policy of Medscape Education to avoid the mention of brand names or specific manufacturers in accredited educational activities. However, manufacturer names related to COVID-19 vaccines may be provided in this activity to promote clarity. The use of manufacturer names should not be viewed as an endorsement by Medscape of any specific product or manufacturer.

Clinical Context

Clinical manifestations of SARS-CoV-2 infection range from asymptomatic to multiple organ failure and death. By November 2021, COVID-19 caused > 5 million deaths globally. Therefore, it is important to identify risk factors to better understand the background etiological mechanisms.

Known risk factors for COVID-19 severity include male sex, older age, preexisting medical conditions, and being from racialized communities. Ambient air pollution has more recently been implicated as a potential driver of COVID-19 severity.

Study Synopsis and Perspective

Patients exposed to common air pollutants are at risk for more severe outcomes after they become infected with the SARS-CoV-2 virus, data suggest.

In a prospective study of more than 150,000 patients with COVID-19, incremental increases in exposure to common pollutants were associated with increases in the risks for hospitalization, admission to an intensive care unit (ICU), or death that ranged from 6% to 30%.

"This study reinforces the idea that air pollution is a pervasive and silent killer and that the association of air pollution and COVID-19 severity reflects the tip of an iceberg of the wide-ranging impacts air pollution has on human health," study author Hong Chen, PhD, MSc, researcher at Public Health Ontario and assistant professor of occupational and environmental health at the University of Toronto, Canada.

The study was published May 24 in theCanadian Medical Association Journal.[1]

Focus of the study

COVID-19 is associated with a tremendous global health burden. Understanding the factors that influence disease severity is important for prevention and treatment, said the investigators.

Exposure to common air pollutants such as fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ground-level ozone (O3) contributes to the global burden of disease. The current investigators evaluated the associations between exposure to these pollutants and indicators of COVID-19 severity.

To identify patients with COVID-19, they examined hospital discharge data from the Health Information Discharge Abstract Database and physician service claims in the Health Insurance Plan database. They used annual exposure surfaces of the 3 pollutants to calculate participants' long-term exposures.

A total of 151,105 people became infected with SARS-CoV-2, the virus that causes COVID-19, in Ontario in 2020. Of this cohort, 5.7% required a COVID-19--related hospital admission, 1.3% required admission to an ICU, and 1.4% died, according to the authors.

The median of long-term exposure to air pollutants was 7.64 µg/m3 for PM2.5, 7.75 ppb for NO2, and 44.8 ppb for O3. In the final, adjusted model, each interquartile range (IQR) increase of 1.7 µg/m3 in exposure to PM2.5 was associated with an odds ratio (OR) of 1.06 for hospital admission and an OR of 1.09 for ICU admission. Although death was positively associated with PM2.5, "we did not observe an effect in the fully adjusted model," said the authors.

In the same model, each IQR increase of 2.5 ppb in exposure to NO2 was associated with an OR of 1.09 for ICU admission. The researchers did not observe any effect of exposure on risk for hospital admission or death.

Each IQR increase of 5.14 ppb in exposure to O3 was associated with an OR of 1.15 for hospital admission, an OR of 1.3 for ICU admission, and an OR of 1.18 for death.

Public Health Implications

"Given the ongoing pandemic, our findings that underscore the link between chronic exposure to air pollution and more severe COVID-19 could have important implications for public health and health systems," said the authors.

Several mechanisms could explain the association between long-term exposure to air pollution and COVID-19 outcomes. First, air pollutants can reduce patients' pulmonary immune responses and antimicrobial activities, boosting viral loads. Pollutants also can induce chronic inflammation and overexpression of the alveolar angiotensin-converting enzyme 2 (ACE) receptor, which facilitates the entry of SARS-CoV-2 into cells. Evidence also has shown that exposure to air pollution increases susceptibility to respiratory viral infections and pneumonia, said Chen.

"It has been suggested that people with chronic conditions and socioeconomically disadvantaged subgroups are more likely to have poorer prognosis after the infection, [because] air pollution has long been known to contribute to poor health among these subgroups," said Chen.

These results support targeted interprofessional public health actions to protect residents from COVID-19 in heavily polluted regions with historically high NO2 levels, according to the authors.

"Rigorous Statistical Modeling"

Commenting on the findings for Medscape Medical News, Donghai Liang, PhD, MPH, assistant professor of environmental health, Emory University, Atlanta, Georgia, said that this prospective cohort study is important and underscores the link between chronic exposure to air pollution and more severe COVID-19.

The impact of ambient air pollution on excess morbidity and mortality has been well established over the past several decades, said Liang.

"In particular, major ubiquitous ambient air pollutants, including PM2.5, NO2, and O3 may have both a direct and an indirect systemic impact on the body by enhancing oxidative stress, inflammation, and respiratory infection risk, eventually leading to numerous adverse health effects," Liang added.

It is therefore possible that long-term exposures to air pollution may have a detrimental effect on COVID-19 outcomes, Liang added. He and his colleagues previously conducted a nationwide study[2] that investigated associations between the same key ambient air pollutants and COVID-19 case fatality and mortality rates in the United States. They reported that long-term exposure to NO2, which largely arises from urban combustion sources such as traffic, may enhance susceptibility to severe COVID-19 outcomes, independent of long-term PM2.5 and O3 exposure.

The study was funded by Health Canada. Chen and Liang have disclosed no relevant financial relationships.

Study Highlights

  • The prospective study cohort included all 151,105 people with confirmed SARS-CoV-2 infection, aged ≥ 20 years and not residing in a long-term care facility in Ontario, Canada, during 2020.
  • Long-term air pollutant exposures were based on residence from 2015 to 2019; median was 7.64 µg/m3 for PM2.5, 7.75 ppb for NO2, and 44.80 ppb for O3.
  • The final model used logistic regression and adjusted for confounders and selection bias using various individual and contextual covariates obtained through data linkage.
  • For each IQR increase in PM2.5 (1.7 μg/m3) exposure, the ORs were 1.06 (95% CI: 1.01, 1.12) for COVID-19--related hospitalization; 1.09 (95% CI: 0.98, 1.21) for ICU admission, and not significant for death (1 [95% CI: 0.9, 1.11]), although PM2.5 exposure was associated with death in earlier, less adjusted models.
  • In the final model, for each IQR increase in NO2 (2.5 ppb) exposure, the OR was 1.09 for ICU admission but not significant for hospitalization or death.
  • For each IQR increase in O3 exposure (5.14 ppb), the OR was 1.15 (95% CI: 1.06, 1.23) for hospitalization, 1.3 (95% CI: 1.12, 1.5) for ICU admission, and 1.18 (95% CI: 1.02, 1.36) for death.
  • In sensitivity analyses, estimates were similar to those of the main model when adjusting for additional covariates, using different exposure windows, restricting to events occurring within 90 days of diagnosis (enrollment date), excluding people with extreme exposures, and accounting for the effect mediated through preexisting conditions caused by air pollution.
  • The investigators concluded that chronic exposure to air pollution, particularly O3, may contribute to severe outcomes after SARS-CoV-2 infection, even when air pollution levels are relatively low.
  • Given the ongoing pandemic, the association between chronic air pollution exposure and more severe COVID-19 has important implications for public health and health systems.
  • Potential mechanisms underlying this association may include pollutants lowering pulmonary immune responses and antimicrobial activity, boosting viral loads.
  • Pollutants may also induce chronic inflammation and overexpression of the alveolar ACE receptor, which facilitates SARS-CoV-2 entry into cells, and air pollution exposure heightens vulnerability to respiratory viral infections and pneumonia.
  • Air pollution exposure contributes to chronic conditions, such as cardiovascular disease, associated with poor COVID-19 outcomes, possibly because of persistent immune activation and excessive amplification of cytokine development.
  • Study limitations include lack of adjustment for race or ethnicity, possible exposure misclassification, and study performed before widespread vaccination against SARS-CoV-2 or use of medications effective against COVID-19.

Clinical Implications

  • Chronic exposure to air pollution, particularly O3, may contribute to severe outcomes after SARS-CoV-2 infection, even when air pollution levels are relatively low.
  • The findings support targeted public health actions to protect residents from COVID-19 in heavily polluted regions with historically high NO2 levels.
  • Implications for the Healthcare Team: Clinicians should work as interprofessional teams to support COVID-19 public health actions, with a focus on patients with chronic conditions and socioeconomically disadvantaged subgroups who reside in heavily polluted regions.

 

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